SnowConvert: Snowflake Scripting¶

BEGIN and COMMIT Transaction¶

Applies to

[x] SQL Server
[x] Azure Synapse Analytics

Description¶

Snowflake SQL, a transaction can be started explicitly by executing a BEGIN statement. Snowflake supports the synonyms BEGIN WORK and BEGIN TRANSACTION. Snowflake recommends using BEGIN TRANSACTION.

A transaction can be ended explicitly by executing COMMIT. Read more about Snowflake Transactions here.

Sample Source Patterns ¶

The following examples detail the BEGIN and COMMIT transaction statements.

Transact-SQL ¶

 CREATE PROCEDURE TestTransaction
AS
BEGIN
    DROP TABLE IF EXISTS NEWTABLE;
    CREATE TABLE NEWTABLE(COL1 INT, COL2 VARCHAR);
      BEGIN TRANSACTION;
         INSERT INTO NEWTABLE VALUES (1, 'MICHAEL');
         INSERT INTO NEWTABLE VALUES(2, 'JACKSON');
      COMMIT TRANSACTION;
END

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 CREATE PROCEDURE TestTransaction
AS
BEGIN
    DROP TABLE IF EXISTS NEWTABLE;
    CREATE TABLE NEWTABLE(COL1 INT, COL2 VARCHAR);
      BEGIN TRANSACTION LabelA;
        INSERT INTO NEWTABLE VALUES (1, 'MICHAEL');
        INSERT INTO NEWTABLE VALUES(2, 'JACKSON');
      COMMIT TRANSACTION LabelA;
END

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Snowflake SQL ¶

 CREATE OR REPLACE PROCEDURE TestTransaction ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
    BEGIN
        DROP TABLE IF EXISTS NEWTABLE;
        CREATE OR REPLACE TABLE NEWTABLE (
            COL1 INT,
            COL2 VARCHAR
        );
            BEGIN TRANSACTION;
            INSERT INTO NEWTABLE VALUES (1, 'MICHAEL');
         INSERT INTO NEWTABLE VALUES(2, 'JACKSON');
            COMMIT;
    END;
$$;

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 CREATE OR REPLACE PROCEDURE TestTransaction ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
    BEGIN
        DROP TABLE IF EXISTS NEWTABLE;
        CREATE OR REPLACE TABLE NEWTABLE (
            COL1 INT,
            COL2 VARCHAR
        );
            BEGIN TRANSACTION
            !!!RESOLVE EWI!!! /*** SSC-EWI-0101 - COMMENTED OUT TRANSACTION LABEL NAME BECAUSE IS NOT APPLICABLE IN SNOWFLAKE ***/!!!
            LabelA;
            INSERT INTO NEWTABLE VALUES (1, 'MICHAEL');
        INSERT INTO NEWTABLE VALUES(2, 'JACKSON');
            COMMIT;
    END;
$$;

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Known Issues¶

Nested transactions are not supported in Snowflake. Review the following documentation for more information: https://docs.snowflake.com/en/sql-reference/transactions

CALL¶

Applies to

[x] SQL Server
[x] Azure Synapse Analytics

Description ¶

The CALL statement is not supported in snowflake scripting since this is part of the ODBC API and not a SQL statement, therefore this statement is not translated.

CASE¶

Applies to

[x] SQL Server
[x] Azure Synapse Analytics

Note

Some parts in the output code are omitted for clarity reasons.

Description¶

Transact-SQL has two possible formats of the Case expression. both of them for the purpose of evaluating expressions and conditionally obtaining results. The first one refers to a Simple Case Expression that will evaluate if an input_expression matches one or more of the when_expression. The second one will evaluate each Boolean_expression independently. The else clause is supported in both formats.

According to the official Transact-SQL Case documentation:

CASE can be used in any statement or clause that allows a valid expression. For example, you can use CASE in statements such as SELECT, UPDATE, DELETE and SET, and in clauses such as select_list, IN, WHERE, ORDER BY, and HAVING.

For more information regarding Transact-SQL Case, check here.

 -- Simple CASE expression:   
CASE input_expression   
     WHEN when_expression THEN result_expression [ ...n ]   
     [ ELSE else_result_expression ]   
END   

-- Searched CASE expression:  
CASE  
     WHEN boolean_expression THEN result_expression [ ...n ]   
     [ ELSE else_result_expression ]   
END

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Note: Transact-SQL allows to optionally encapsulate the input_expression and the boolean_expression in parentheses; Snowflake Scripting too.

Sample Source Patterns ¶

The following examples detail two scenarios where the Case expression can be used and their differences from Snowflake Scripting.

Select using Case¶

Transact-SQL¶

 CREATE OR ALTER PROCEDURE SelectCaseDemoProcedure
AS
      SELECT TOP 10
          LOGINID,
          CASE (MARITALSTATUS)
              WHEN 'S' THEN 'SINGLE'
              WHEN 'M' THEN 'MARIED'
              ELSE 'OTHER'
          END AS status
      FROM HUMANRESOURCES.EMPLOYEE;
GO

EXEC SelectCaseDemoProcedure;

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 CREATE OR ALTER PROCEDURE SelectCaseDemoProcedure
AS
      SELECT TOP 10
          LOGINID,
          CASE
              WHEN MARITALSTATUS = 'S' THEN 'SINGLE'
              WHEN MARITALSTATUS = 'M' THEN 'MARIED'
              ELSE 'OTHER'
          END AS status
      FROM HUMANRESOURCES.EMPLOYEE;
GO

EXEC SelectCaseDemoProcedure;

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 sqlLOGINID              |status|
------------------------+------+
adventure-works\ken0    |SINGLE|
adventure-works\terri0  |SINGLE|
adventure-works\roberto0|MARIED|
adventure-works\rob0    |SINGLE|
adventure-works\gail0   |MARIED|
adventure-works\jossef0 |MARIED|
adventure-works\dylan0  |MARIED|
adventure-works\diane1  |SINGLE|
adventure-works\gigi0   |MARIED|
adventure-works\michael6|MARIED|

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Snowflake Scripting ¶

Note that in this scenario there are no differences regarding the Case expression itself.

Warning

The declaration and assignment of the res variable is in order to demonstrate the functional equivalence between both languages. It does not appear in the actual output.

CREATE OR REPLACE PROCEDURE SelectCaseDemoProcedure ()
RETURNS TABLE()
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
      DECLARE
            ProcedureResultSet RESULTSET;
      BEGIN
            ProcedureResultSet := (
            SELECT TOP 10
                  LOGINID,
                CASE (MARITALSTATUS)
                    WHEN 'S' THEN 'SINGLE'
                    WHEN 'M' THEN 'MARIED'
                    ELSE 'OTHER'
                END AS status
            FROM
                  HUMANRESOURCES.EMPLOYEE);
            RETURN TABLE(ProcedureResultSet);
      END;
$$;

CALL SelectCaseDemoProcedure();

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 CREATE OR REPLACE PROCEDURE SelectCaseDemoProcedure ()
RETURNS TABLE()
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
      DECLARE
            ProcedureResultSet RESULTSET;
      BEGIN
            ProcedureResultSet := (
            SELECT TOP 10
                  LOGINID,
                CASE
                    WHEN MARITALSTATUS = 'S' THEN 'SINGLE'
                    WHEN MARITALSTATUS = 'M' THEN 'MARIED'
                    ELSE 'OTHER'
                END AS status
            FROM
                  HUMANRESOURCES.EMPLOYEE);
            RETURN TABLE(ProcedureResultSet);
      END;
$$;

CALL SelectCaseDemoProcedure();

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 LOGINID                |STATUS|
-----------------------+------+
adventure-worksken0    |SINGLE|
adventure-works erri0  |SINGLE|
adventure-worksoberto0 |MARIED|
adventure-worksob0     |SINGLE|
adventure-worksgail0   |MARIED|
adventure-worksjossef0 |MARIED|
adventure-worksdylan0  |MARIED|
adventure-worksdiane1  |SINGLE|
adventure-worksgigi0   |MARIED|
adventure-worksmichael6|MARIED|

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Set using Case¶

The AdventureWorks2019 database was used in both languages to obtain the same results.

Transact-SQL¶

 CREATE OR ALTER PROCEDURE SetCaseDemoProcedure
AS
    DECLARE @value INT;
    DECLARE @result INT;
    SET @value = 5;
    
    SET @result =
        CASE @value
            WHEN 1 THEN @value * 10
            WHEN 3 THEN @value * 20
            WHEN 5 THEN @value * 30
            WHEN 7 THEN @value * 40
            ELSE -1
        END;
    
    RETURN @result
GO

DECLARE @result INT;
EXEC @result = SetCaseDemoProcedure;
PRINT @result;

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 CREATE OR ALTER PROCEDURE SetCaseDemoProcedure
AS
    DECLARE @value INT;
    DECLARE @result INT;
    SET @value = 5;
    
    SET @result =
        CASE
            WHEN @value = 1 THEN @value * 10
            WHEN @value = 3 THEN @value * 20
            WHEN @value = 5 THEN @value * 30
            WHEN @value = 7 THEN @value * 40
            ELSE -1
        END;
    
    RETURN @result
GO

DECLARE @result INT;
EXEC @result = SetCaseDemoProcedure;
PRINT @result;

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 |result|
|------|
|150   |

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Snowflake Scripting ¶

Warning

Snowflake Scripting does not allow to set a case expression directly to a variable. Both Transact-SQL Case expression formats translate to the following grammar in Snowflake Scripting.

 CREATE OR REPLACE PROCEDURE SetCaseDemoProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
    DECLARE
        VALUE INT;
        RESULT INT;
    BEGIN
         
         
        VALUE := 5;
        CASE (:VALUE)
            WHEN 1 THEN
                RESULT := :VALUE * 10;
            WHEN 3 THEN
                RESULT := :VALUE * 20;
            WHEN 5 THEN
                RESULT := :VALUE * 30;
            WHEN 7 THEN
                RESULT := :VALUE * 40;
            ELSE
                RESULT := -1;
        END;
        RETURN :RESULT;
    END;
$$;

DECLARE
    RESULT INT;
BEGIN
    CALL SetCaseDemoProcedure();
    !!!RESOLVE EWI!!! /*** SSC-EWI-0073 - PENDING FUNCTIONAL EQUIVALENCE REVIEW FOR 'Print' NODE ***/!!!
    PRINT @result;
END;

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CREATE OR REPLACE PROCEDURE SetCaseDemoProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
    DECLARE
        VALUE INT;
        RESULT INT;
    BEGIN
         
         
        VALUE := 5;
        CASE
            WHEN :VALUE = 1 THEN
                RESULT := :VALUE * 10;
            WHEN :VALUE = 3 THEN
                RESULT := :VALUE * 20;
            WHEN :VALUE = 5 THEN
                RESULT := :VALUE * 30;
            WHEN :VALUE = 7 THEN
                RESULT := :VALUE * 40;
            ELSE
                RESULT := -1;
        END;
        RETURN :RESULT;
    END;
$$;

DECLARE
    RESULT INT;
BEGIN
    CALL SetCaseDemoProcedure();
    !!!RESOLVE EWI!!! /*** SSC-EWI-0073 - PENDING FUNCTIONAL EQUIVALENCE REVIEW FOR 'Print' NODE ***/!!!
    PRINT @result;
END;

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 |result|
|------|
|150   |

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Known Issues¶

No issues were found.

Related EWIs¶

SSC-EWI-0073: Pending Functional Equivalence Review.

CREATE PROCEDURE¶

Applies to

[x] SQL Server
[x] Azure Synapse Analytics

Note

Some parts in the output code are omitted for clarity reasons.

Description¶

The create procedure statement allows the creation of stored procedures that can:

Accept input parameters and return multiple values in the form of output parameters to the calling procedure or batch.
Contain programming statements that perform operations in the database, including calling other procedures.
Return a status value to a calling procedure or batch to indicate success or failure (and the reason for failure).

For more information regarding Transact-SQL CREATE PROCEDURE, check here.

 CREATE [ OR ALTER ] { PROC | PROCEDURE }
    [schema_name.] procedure_name [ ; number ]
    [ { @parameter [ type_schema_name. ] data_type }
        [ VARYING ] [ = default ] [ OUT | OUTPUT | [READONLY]
    ] [ ,...n ]
[ WITH <procedure_option> [ ,...n ] ]
[ FOR REPLICATION ]
AS { [ BEGIN ] sql_statement [;] [ ...n ] [ END ] }
[;]

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Sample Source Patterns¶

Stored procedure without body¶

A stored procedure without a body is an unusual scenario that is allowed in Transact-SQL. Snowflake Scripting does not allow to define procedures without a body, but the following example shows the equivalence.

Transact-SQL¶

 CREATE PROC SampleProcedure AS;

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Snowflake Scripting¶

 CREATE OR REPLACE PROCEDURE SampleProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
   BEGIN
      RETURN '';
   END;
$$;

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Basic stored procedure¶

The following example details a simple stored procedure that will include a new Privacy department into the AdventureWorks2019 database.

Transact-SQL¶

 CREATE OR ALTER PROCEDURE Add_Privacy_Department
AS
  EXECUTE ('INSERT INTO HumanResources.Department VALUES (''Privacy'', ''Executive General and Administration'', default)');

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Snowflake Scripting¶

 CREATE OR REPLACE PROCEDURE Add_Privacy_Department ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
  BEGIN
    !!!RESOLVE EWI!!! /*** SSC-EWI-0030 - THE STATEMENT BELOW HAS USAGES OF DYNAMIC SQL. ***/!!!
    EXECUTE IMMEDIATE 'INSERT INTO HumanResources.Department VALUES ('Privacy', 'Executive General and Administration', default);';
  END;
$$;

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Alter procedure¶

The transformation for the ALTER procedure is equivalent to the basic procedure.

Transact-SQL¶

 ALTER PROCEDURE procedureName
AS
SELECT 1 AS ThisDB;

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Snowflake Scripting¶

 CREATE OR REPLACE PROCEDURE procedureName ()
RETURNS TABLE()
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
DECLARE
ProcedureResultSet RESULTSET;
BEGIN
ProcedureResultSet := (
SELECT 1 AS ThisDB);
RETURN TABLE(ProcedureResultSet);
END;
$$;

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Using parameters¶

You can use parameters to drive your logic or construct dynamic SQL statements inside your stored procedure. In the following example a simple SetNewPrice stored procedure is constructed, which sets a new product price based on the arguments sent by the caller.

Transact-SQL¶

 CREATE OR ALTER PROCEDURE SetNewPrice @ProductID INT, @NewPrice MONEY
AS
  BEGIN
    DECLARE @dynSqlStatement AS VARCHAR(300);
    SET @dynSqlStatement = 'UPDATE Production.ProductListPriceHistory SET ListPrice = ' + CAST(@NewPrice AS VARCHAR(10)) + ' WHERE ProductID = ' + CAST(@ProductID AS VARCHAR(10)) + ' AND EndDate IS NULL';
    EXECUTE (@dynSqlStatement);
  END;

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Snowflake Scripting¶

 CREATE OR REPLACE PROCEDURE SetNewPrice (PRODUCTID INT, NEWPRICE NUMBER(38, 4))
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
  DECLARE
    DYNSQLSTATEMENT VARCHAR(300);
  BEGIN
     
    DYNSQLSTATEMENT := 'UPDATE Production.ProductListPriceHistory
   SET
      ListPrice = ' || CAST(:NEWPRICE AS VARCHAR(10)) || '
   WHERE
      ProductID = ' || CAST(:PRODUCTID AS VARCHAR(10)) || '
      AND EndDate IS NULL;';
    !!!RESOLVE EWI!!! /*** SSC-EWI-0030 - THE STATEMENT BELOW HAS USAGES OF DYNAMIC SQL. ***/!!!
    EXECUTE IMMEDIATE :DYNSQLSTATEMENT;
  END;
$$;

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Output Parameters¶

Transact-SQL output keyword indicates that the parameter is an output parameter, which value will be returned to the stored procedure caller. For example, the following procedure will return the number of vacation hours of a specific employee.

Transact-SQL¶

 CREATE PROCEDURE GetVacationHours  
   @employeeId INT,  
   @vacationHours INT OUTPUT  
AS  
BEGIN  
   SELECT @vacationHours = VacationHours 
   FROM HumanResources.Employee
   WHERE NationalIDNumber = @employeeID
END;

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Snowflake Scripting¶

 CREATE OR REPLACE PROCEDURE GetVacationHours (EMPLOYEEID INT, VACATIONHOURS INT)
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
   BEGIN
      SELECT
         VacationHours
      INTO
         :VACATIONHOURS
      FROM
         HumanResources.Employee
      WHERE
         NationalIDNumber = :EMPLOYEEID;
      RETURN VACATIONHOURS;
   END;
$$;

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Warning

Only 1 output parameter can be returned from a Snowflake scripting stored procedure.

Optional Parameters¶

A parameter is considered optional if the parameter has a default value specified when it is declared. It is not necessary to provide a value for an optional parameter in a procedure call.

Transact-SQL¶

 CREATE PROCEDURE OPTIONAL_PARAMETER @VAR1 INT = 1, @VAR2 INT = 2
AS
    BEGIN
        RETURN NULL;
    END

GO

EXEC OPTIONAL_PARAMETER @VAR2 = 4

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Snowflake Scripting¶

 CREATE OR REPLACE PROCEDURE OPTIONAL_PARAMETER (VAR1 INT DEFAULT 1, VAR2 INT DEFAULT 2)
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
    BEGIN
        RETURN NULL;
    END;
$$;

CALL OPTIONAL_PARAMETER(VAR2 => 4);

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EXECUTE AS¶

Transact-SQL’s EXECUTE AS clause defines the execution context of the stored procedure, specifying which user account the Database Engine uses to validate permissions on objects that are referenced within the procedure. For example, we can modify the previous GetVacationHours procedure to define different execution contexts.

Owner (default in Snowflake Scripting)

Transact-SQL¶

CREATE OR ALTER PROCEDURE GetVacationHours
   @employeeId INT,  
   @vacationHours INT OUTPUT
WITH EXECUTE AS OWNER
AS
BEGIN  
   SELECT @vacationHours = VacationHours 
   FROM HumanResources.Employee
   WHERE NationalIDNumber = @employeeID
END;

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Snowflake Scripting¶

 CREATE OR REPLACE PROCEDURE GetVacationHours (EMPLOYEEID INT, VACATIONHOURS INT)
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
EXECUTE AS OWNER
AS
$$
   BEGIN
      SELECT
         VacationHours
      INTO
         :VACATIONHOURS
      FROM
         HumanResources.Employee
      WHERE
         NationalIDNumber = :EMPLOYEEID;
      RETURN VACATIONHOURS;
   END;
$$;

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Caller

Transact-SQL¶

 CREATE OR ALTER PROCEDURE GetVacationHours
   @employeeId INT,  
   @vacationHours INT OUTPUT
WITH EXECUTE AS CALLER
AS
BEGIN  
   SELECT @vacationHours = VacationHours 
   FROM HumanResources.Employee
   WHERE NationalIDNumber = @employeeID
END;

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Snowflake Scripting¶

 CREATE OR REPLACE PROCEDURE GetVacationHours (EMPLOYEEID INT, VACATIONHOURS INT)
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
   BEGIN
      SELECT
         VacationHours
      INTO
         :VACATIONHOURS
      FROM
         HumanResources.Employee
      WHERE
         NationalIDNumber = :EMPLOYEEID;
      RETURN VACATIONHOURS;
   END;
$$;

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Warning

SELF and specific user (‘user_name’) execution contexts are not supported in Snowflake Scripting.

READONLY AND VARYING PARAMETERS¶

Snowflake does not support READONLY and VARYING parameter types, an FDM is added instead.

Transact-SQL¶

 CREATE OR ALTER PROCEDURE GetVacationHours
   @Param1 INT READONLY,  
   @Param2 INT VARYING
AS
BEGIN  
   SELECT * FROM Table1;
END;

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Snowflake Scripting¶

 CREATE OR REPLACE PROCEDURE GetVacationHours (PARAM1 INT !!!RESOLVE EWI!!! /*** SSC-EWI-0058 - FUNCTIONALITY FOR 'READONLY PARAMETERS' IS NOT CURRENTLY SUPPORTED BY SNOWFLAKE SCRIPTING ***/!!!, PARAM2 INT !!!RESOLVE EWI!!! /*** SSC-EWI-0058 - FUNCTIONALITY FOR 'VARYING PARAMETERS' IS NOT CURRENTLY SUPPORTED BY SNOWFLAKE SCRIPTING ***/!!!)
RETURNS TABLE()
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
   DECLARE
      ProcedureResultSet RESULTSET;
   BEGIN
      ProcedureResultSet := (
      SELECT
         *
      FROM
         Table1);
      RETURN TABLE(ProcedureResultSet);
   END;
$$;

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Known Issues¶

Unsupported Optional Arguments¶

[VARYING] Applies only to cursor parameters.Specifies the result set supported as an output parameter. This parameter is dynamically constructed by the procedure and its contents may vary. Snowflake scripting does not support CURSOR as a valid return data type.
[= default] Makes a parameter optional through the definition of a default value. Snowflake scripting does not natively supports default parameter values.
[READONLY] Indicates that the parameter cannot be updated or modified within the body of the procedure. Currently unsupported in Snowflake Scripting.
[WITH RECOMPILE] Forces the database engine to compile the stored procedure’s query plan each time it is executed. Currently unsupported in Snowflake Scripting.
[WITH ENCRYPTION] Used to encrypt the text of a stored procedure. Only users with access to system tables or database files (such as sysadmin users) will be able to access the procedure text after its creation. Currently unsupported in Snowflake Scripting.
[FOR REPLICATION] Restricts the stored procedure to be executed only during replication. Currently unsupported in Snowflake Scripting.

Related EWIS¶

SSC-EWI-0030: The statement below has usages of dynamic SQL.
SSC-EWI-0058: Functionality is not currently supported by Snowflake Scripting.

CURSOR¶

Applies to

[x] SQL Server
[x] Azure Synapse Analytics

Note

Some parts in the output code are omitted for clarity reasons.

Description¶

Transact-SQL statements produce a complete result set, but there are times when the results are best processed one row at a time. Opening a cursor on a result set allows processing the result set one row at a time. You can assign a cursor to a variable or parameter with a cursor data type. For more information check here.

 //ISO Syntax  
DECLARE cursor_name [ INSENSITIVE ] [ SCROLL ] CURSOR   
     FOR select_statement   
     [ FOR { READ ONLY | UPDATE [ OF column_name [ ,...n ] ] } ]  
[;]  

//Transact-SQL Extended Syntax  
DECLARE cursor_name CURSOR [ LOCAL | GLOBAL ]   
     [ FORWARD_ONLY | SCROLL ]   
     [ STATIC | KEYSET | DYNAMIC | FAST_FORWARD ]   
     [ READ_ONLY | SCROLL_LOCKS | OPTIMISTIC ]   
     [ TYPE_WARNING ]   
     FOR select_statement   
     [ FOR UPDATE [ OF column_name [ ,...n ] ] ]  
[;]  

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 FETCH   
          [ [ NEXT | PRIOR | FIRST | LAST   
                    | ABSOLUTE { n | @nvar }   
                    | RELATIVE { n | @nvar }   
               ]   
               FROM   
          ]   
{ { [ GLOBAL ] cursor_name } | @cursor_variable_name }   
[ INTO @variable_name [ ,...n ] ] 

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 OPEN { { [ GLOBAL ] cursor_name } | cursor_variable_name }  

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 CLOSE { { [ GLOBAL ] cursor_name } | cursor_variable_name }

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 DEALLOCATE { { [ GLOBAL ] cursor_name } | @cursor_variable_name }  

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Sample Source Patterns¶

Transact-SQL¶

Notice that the following parameters are inherently supported by Snowflake Scripting.

[LOCAL].
[FORWARD_ONLY].
[FAST_FORWARD] Specifies a FORWARD_ONLY (FETCH NEXT only) and READ_ONLY
[READ_ONLY] the WHERE CURRENT OF does not exist in Snowflake Scripting.

 CREATE TABLE vEmployee   (
    PersonID INT,
    LastName VARCHAR(255),
    FirstName VARCHAR(255),
);

INSERT INTO vEmployee(PersonID, LastName, FirstName) 
VALUES
    (1, 'AA', 'A'),
    (2, 'BB', 'B'),
    (3, 'CC', 'C'),
    (4, 'DD', 'D'),
    (5, 'EE', 'E'),
    (6, 'FF', 'F'),
    (7, 'GG', 'G');
	
CREATE OR ALTER PROCEDURE CursorExample
AS
    DECLARE 
        @CursorVar CURSOR, 
	@firstName VARCHAR;

    SET @CursorVar = CURSOR LOCAL FORWARD_ONLY STATIC READ_ONLY 
	FOR  
	SELECT FirstName
	FROM vEmployee;  

    OPEN @CursorVar;

    FETCH NEXT FROM @CursorVar INTO @firstName;
    FETCH NEXT FROM @CursorVar INTO @firstName;

    CLOSE @CursorVar;

    SELECT @firstName;
GO

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Snowflake Scripting¶

 CREATE OR REPLACE TABLE vEmployee (
	PersonID INT,
	LastName VARCHAR(255),
	FirstName VARCHAR(255)
)
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"transact"}}'
;

INSERT INTO vEmployee (PersonID, LastName, FirstName)
VALUES
    (1, 'AA', 'A'),
    (2, 'BB', 'B'),
    (3, 'CC', 'C'),
    (4, 'DD', 'D'),
    (5, 'EE', 'E'),
    (6, 'FF', 'F'),
    (7, 'GG', 'G');

CREATE OR REPLACE PROCEDURE CursorExample ()
RETURNS TABLE()
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
	DECLARE
		CURSORVAR CURSOR
		FOR
			SELECT FirstName
			FROM vEmployee;
		FIRSTNAME VARCHAR;
		ProcedureResultSet RESULTSET;
	BEGIN
		 
		 
		OPEN CURSORVAR;
		FETCH
			CURSORVAR
		INTO
			:FIRSTNAME;
		FETCH
			CURSORVAR
		INTO
			:FIRSTNAME;
		CLOSE CURSORVAR;
		ProcedureResultSet := (
		SELECT
			:FIRSTNAME);
		RETURN TABLE(ProcedureResultSet);
	END;
$$;

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Known Issues¶

The following parameters are not supported:

DECLARE CURSOR

[ GLOBAL ] Allows referencing the cursor name in any stored procedure or batch executed by the connection. Snowflake Scripting only allows the use of the cursor locally.
[ SCROLL ] Snowflake Scripting only support FETCH NEXT.
[ KEYSET | DYNAMIC ] If after opening a cursor and update to the table is made, these options may display some of the changes when fetching the cursor, Snowflake scripting only supports STATIC, in other words, after the cursor is opened the changes to the table are not detected by the cursor.
[SCROLL_LOCKS] Specifies that positioned updates or deletes made through the cursor are guaranteed to succeed, Snowflake Scripting cannot guarantee it.
[OPTIMISTIC] When an update or delete is made through the cursor it uses comparisons of timestamp column values, or a checksum value if the table has no timestamp column, to determine whether the row was modified after it was read into the cursor. Snowflake Scripting does not have an internal process to replicate it.
[TYPE_WARNING]

FETCH

[PRIOR | FIRST | LAST] Snowscripting only support NEXT.
[ABSOLUTE] Snowflake Scripting only supports NEXT but the behavior can be replicated.
[RELATIVE] Snowflake Scripting but the behavior can be replicated.
[ GLOBAL ] Allows referencing the cursor name in any stored procedure or batch executed by the connection. Snowflake Scripting only allows the use of the cursor locally.
FETCH without INTO is not supported.
When the FETCH statement is located inside a loop it is considered a complex pattern as it may have an impact on the Snowflake translated code performance. Check the related issues section for more information.

Fetch inside loop sample¶

 CREATE OR ALTER PROCEDURE cursor_procedure1
AS
BEGIN
DECLARE cursor1 CURSOR FOR SELECT col1 FROM my_table;
WHILE 1=0
   BEGIN
      FETCH NEXT FROM @cursor1 INTO @variable1;
   END
END;

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 CREATE OR REPLACE PROCEDURE cursor_procedure1 ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
   DECLARE
      --** SSC-FDM-TS0013 - SNOWFLAKE SCRIPTING CURSOR ROWS ARE NOT MODIFIABLE **
      cursor1 CURSOR
      FOR
         SELECT
            col1
         FROM
            my_table;
   BEGIN
       
      WHILE (1=0) LOOP
         --** SSC-PRF-0003 - FETCH INSIDE A LOOP IS CONSIDERED A COMPLEX PATTERN, THIS COULD DEGRADE SNOWFLAKE PERFORMANCE. **
         FETCH
            CURSOR1
            INTO
            :VARIABLE1;
      END LOOP;
   END;
$$;

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OPEN

[ GLOBAL ] Allows referencing the cursor name in any stored procedure or batch executed by the connection. Snowflake Scripting only allows the use of the cursor locally.

[ GLOBAL ] Allows referencing the cursor name in any stored procedure or batch executed by the connection. Snowflake Scripting only allows the use of the cursor locally.

DEALLOCATED Removes a cursor reference and there is no equivalent in Snowflake Scripting.

WHERE CURRENT OF the use of this statement is not supported, for example:

 CREATE OR ALTER PROCEDURE CursorWithCurrent
AS
    DECLARE 
        @CursorVar CURSOR;

    SET @CursorVar = CURSOR 
	FOR  
	SELECT FirstName  
	FROM vEmployee;  

    OPEN @CursorVar;

    FETCH NEXT FROM @CursorVar;
    FETCH NEXT FROM @CursorVar;

    UPDATE vEmployee SET LastName = 'Changed' WHERE CURRENT OF @CursorVar;

    CLOSE @CursorVar;
GO

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Environment variables

@@CURSOR_ROWS
@@FETCH_STATUS

Related EWIs¶

SSC-FDM-TS0013: Snowflake Scripting cursor rows are not modifiable.
SSC-PRF-0003: Fetch inside a loop is considered a complex pattern, this could degrade Snowflake performance.

DECLARE¶

Applies to

[x] SQL Server
[x] Azure Synapse Analytics

Description¶

Transact-SQL DECLARE statement allows the creation of variables that can be used in the scope of the batch or a stored procedure. For more information regarding Transact-SQL DECLARE, check here.

 -- Syntax for SQL Server and Azure SQL Database  
  
DECLARE   
{   
    { @local_variable [AS] data_type  [ = value ] }  
  | { @cursor_variable_name CURSOR }  
} [,...n]   
| { @table_variable_name [AS] <table_type_definition> }   
  
<table_type_definition> ::=   
     TABLE ( { <column_definition> | <table_constraint> } [ ,...n] )   
  
<column_definition> ::=   
     column_name { scalar_data_type | AS computed_column_expression }  
     [ COLLATE collation_name ]   
     [ [ DEFAULT constant_expression ] | IDENTITY [ (seed ,increment ) ] ]   
     [ ROWGUIDCOL ]   
     [ <column_constraint> ]   
  
<column_constraint> ::=   
     { [ NULL | NOT NULL ]   
     | [ PRIMARY KEY | UNIQUE ]   
     | CHECK ( logical_expression )   
     | WITH ( <index_option > )  
     }   
  
<table_constraint> ::=   
     { { PRIMARY KEY | UNIQUE } ( column_name [ ,...n] )   
     | CHECK ( search_condition )   
     }

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Sample Source Patterns¶

Declare variables¶

Variables can be created in different ways. Variables may or may not have a default value and several variables can be declared in the same line.

Notice that Snowflake Scripting does not allow to create more than one variable per line.

Transact-SQL¶

 DECLARE @find VARCHAR(30);
DECLARE @find2 VARCHAR(30) = 'Default';
DECLARE @var VARCHAR(5), @var2 varchar(5);

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Snowflake Scripting

 DECLARE
FIND VARCHAR(30);
FIND2 VARCHAR(30) := 'Default';
VAR VARCHAR(5);
VAR2 VARCHAR(5);
BEGIN
RETURN '';
END;

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Declare table variables¶

Transact-SQL allows the creation of table variables that can be used as regular tables. Snowflake scripting does not support this, instead, a table can be created and then dropped at the end of the procedure.

Transact-SQL¶

 DECLARE @MyTableVar TABLE(  
    column1 varchar(10));

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Snowflake Scripting

 BEGIN
    DECLARE
        T_MYTABLEVAR TABLE(
            column1 VARCHAR(10));
END;

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DECLARE statement outside routines (functions and procedures)¶

Unlike Transact-SQL, Snowflake does not support executing isolated statements like DECLARE outside routines like functions or procedures. For this scenario, the statement should be encapsulated in an anonymous block, as shown in the following examples. This statement is usually used before a SET STATEMENT.

Transact-SQL¶

 DECLARE @Group nvarchar(50), @Sales MONEY;
SET @Group = N'North America';
SET @Sales = 2000000;

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Snowflake Scripting

 DECLARE
_GROUP VARCHAR(50);
SALES NUMBER(38, 4);
BEGIN
_GROUP := 'North America';
SALES := 2000000;
END;

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If there is a scenario with only DECLARE statements, the BEGIN…END block should have a RETURN NULL statement to avoid errors, since this block can’t be empty.

Transact-SQL¶

 DECLARE @Group nvarchar(50), @Sales MONEY;

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Snowflake Scripting

 DECLARE
_GROUP VARCHAR(50);
SALES NUMBER(38, 4);
BEGIN
RETURN '';
END;

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Known Issues¶

No issues were found.

Related EWIs¶

No related EWIs.

EXECUTE¶

Applies to

[x] SQL Server
[x] Azure Synapse Analytics

Note

Some parts in the output code are omitted for clarity reasons.

Description¶

Transact-SQL EXECUTE statement allows the execution of a command string or character string within a Transact-SQL batch, a scalar-valued user-defined function, or a stored procedure. For more information regarding Transact-SQL EXECUTE, check here.

 -- Execute a character string  
{ EXEC | EXECUTE }   
    ( { @string_variable | [ N ]'tsql_string' } [ + ...n ] )  
    [ AS { LOGIN | USER } = ' name ' ]  
[;]  

-- Execute a stored procedure or function  
[ { EXEC | EXECUTE } ]  
    {   
      [ @return_status = ]  
      { module_name [ ;number ] | @module_name_var }   
        [ [ @parameter = ] { value   
                           | @variable [ OUTPUT ]   
                           | [ DEFAULT ]   
                           }  
        ]  
      [ ,...n ]  
      [ WITH <execute_option> [ ,...n ] ]  
    }  
[;]  

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Sample Source Patterns¶

Execution of character string¶

EXECUTE can be used to perform SQL operations passed directly as literals. In the following example it is used within a stored procedure that will insert a new privacy department into the AdventureWorks2019 database.

Transact-SQL¶

 CREATE OR ALTER PROCEDURE AddPrivacyDepartment
AS 
EXECUTE ('INSERT INTO HumanResources.Department VALUES (''Privacy'', ''Executive General and Administration'', default)');

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Snowflake Scripting¶

 CREATE OR REPLACE PROCEDURE AddPrivacyDepartment ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
BEGIN
!!!RESOLVE EWI!!! /*** SSC-EWI-0030 - THE STATEMENT BELOW HAS USAGES OF DYNAMIC SQL. ***/!!!
EXECUTE IMMEDIATE 'INSERT INTO HumanResources.Department VALUES ('Privacy', 'Executive General and Administration', default);';
END;
$$;

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Execution of stored procedure¶

EXECUTE can also be used to call an existing stored procedure. The following example will call the AddPrivacyDepartment procedure that was created above. It will then run a SELECT to verify that the new department was successfully included.

Transact-SQL¶

 EXECUTE AddPrivacyDepartment;
SELECT DepartmentID, Name, GroupName FROM HumanResources.Department; 

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DepartmentID|Name                      |GroupName                           |ModifiedDate           |
------------+--------------------------+------------------------------------+-----------------------+
           1|Engineering               |Research and Development            |2008-04-30 00:00:00.000|
           2|Tool Design               |Research and Development            |2008-04-30 00:00:00.000|
           3|Sales                     |Sales and Marketing                 |2008-04-30 00:00:00.000|
           4|Marketing                 |Sales and Marketing                 |2008-04-30 00:00:00.000|
           5|Purchasing                |Inventory Management                |2008-04-30 00:00:00.000|
           6|Research and Development  |Research and Development            |2008-04-30 00:00:00.000|
           7|Production                |Manufacturing                       |2008-04-30 00:00:00.000|
           8|Production Control        |Manufacturing                       |2008-04-30 00:00:00.000|
           9|Human Resources           |Executive General and Administration|2008-04-30 00:00:00.000|
          10|Finance                   |Executive General and Administration|2008-04-30 00:00:00.000|
          11|Information Services      |Executive General and Administration|2008-04-30 00:00:00.000|
          12|Document Control          |Quality Assurance                   |2008-04-30 00:00:00.000|
          13|Quality Assurance         |Quality Assurance                   |2008-04-30 00:00:00.000|
          14|Facilities and Maintenance|Executive General and Administration|2008-04-30 00:00:00.000|
          15|Shipping and Receiving    |Inventory Management                |2008-04-30 00:00:00.000|
          16|Executive                 |Executive General and Administration|2008-04-30 00:00:00.000|
          17|Privacy                   |Executive General and Administration|2021-11-17 12:42:54.640|

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Snowflake Scripting¶

 CALL AddPrivacyDepartment();

SELECT
DepartmentID,
Name,
GroupName
FROM
HumanResources.Department;

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DEPARTMENTID|NAME                      |GROUPNAME                           |MODIFIEDDATE           |
------------+--------------------------+------------------------------------+-----------------------+
           1|Engineering               |Research and Development            |2021-11-17 10:29:36.963|
           2|Tool Design               |Research and Development            |2021-11-17 10:29:37.463|
           3|Sales                     |Sales and Marketing                 |2021-11-17 10:29:38.192|
           4|Marketing                 |Sales and Marketing                 |2021-11-17 10:29:38.733|
           5|Purchasing                |Inventory Management                |2021-11-17 10:29:39.298|
           6|Research and Development  |Research and Development            |2021-11-17 10:31:53.770|
           7|Production                |Manufacturing                       |2021-11-17 10:31:55.082|
           8|Production Control        |Manufacturing                       |2021-11-17 10:31:56.638|
           9|Human Resources           |Executive General and Administration|2021-11-17 10:31:57.507|
          10|Finance                   |Executive General and Administration|2021-11-17 10:31:58.473|
          11|Information Services      |Executive General and Administration|2021-11-17 10:34:35.200|
          12|Document Control          |Quality Assurance                   |2021-11-17 10:34:35.741|
          13|Quality Assurance         |Quality Assurance                   |2021-11-17 10:34:36.277|
          14|Facilities and Maintenance|Executive General and Administration|2021-11-17 10:34:36.832|
          15|Shipping and Receiving    |Inventory Management                |2021-11-17 10:34:37.373|
          16|Executive                 |Executive General and Administration|2021-11-17 10:34:37.918|
          17|Privacy                   |Executive General and Administration|2021-11-17 10:46:43.345|

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Execution of local variable and use of parameters¶

A common use case for the EXECUTE statement is when dynamic SQL statements are needed. In this cases instead of executing a string literal, the statement could be constructed dynamically and assigned to a local variable, which will then be executed. A set of arguments can be sent to the called stored procedure to construct the dynamic SQL command.

In the following example a simple SetNewPrice stored procedure is constructed, which uses the EXECUTE statement to set a new product price based on the arguments sent by the caller. Lastly a SELECT is performed to confirm the new product price.

Transact-SQL¶

 CREATE OR ALTER PROCEDURE SetNewPrice @ProductID INT, @NewPrice MONEY
AS
  DECLARE @dynSqlStatement AS VARCHAR(300);
  SET @dynSqlStatement = 'UPDATE Production.ProductListPriceHistory SET ListPrice = ' + CAST(@NewPrice AS VARCHAR(10)) + ' WHERE ProductID = ' + CAST(@ProductID AS VARCHAR(10)) + ' AND EndDate IS NULL';
  EXECUTE (@dynSqlStatement);
GO

EXECUTE Set_New_Price @ProductID = 707, @NewPrice = 34.99;
SELECT ListPrice FROM Production.ProductListPriceHistory WHERE ProductID = 707 AND EndDate IS NULL;

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ListPrice|
---------+
  34.9900|

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Snowflake Scripting¶

 CREATE OR REPLACE PROCEDURE SetNewPrice (PRODUCTID INT, NEWPRICE NUMBER(38, 4))
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
  DECLARE
    DYNSQLSTATEMENT VARCHAR(300);
  BEGIN
     
    DYNSQLSTATEMENT := 'UPDATE Production.ProductListPriceHistory
   SET
      ListPrice = ' || CAST(:NEWPRICE AS VARCHAR(10)) || '
   WHERE
      ProductID = ' || CAST(:PRODUCTID AS VARCHAR(10)) || '
      AND EndDate IS NULL;';
    !!!RESOLVE EWI!!! /*** SSC-EWI-0030 - THE STATEMENT BELOW HAS USAGES OF DYNAMIC SQL. ***/!!!
    EXECUTE IMMEDIATE :DYNSQLSTATEMENT;
  END;
$$;

CALL Set_New_Price(707, 34.99);

SELECT
  ListPrice
FROM
  Production.ProductListPriceHistory
WHERE
  ProductID = 707 AND EndDate IS NULL;

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LISTPRICE|
---------+
  34.9900|

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Known Issues¶

Using return codes¶

Transact-SQL EXECUTE syntax contains the @return_status optional argument, which allows creating a scalar variable to store the return status of a scalar-valued user defined function.

It can also be used in stored procedures although the returning status will be limited to integer data type.

To represent this functionality, we could slightly modify the above example and create a user defined function to calculate the new product price as an average of the historical prices. Instead of passing it to the stored procedure, we could now call the CalculateAveragePrice function to obtain the new price, and store it in the return variable to construct the dynamic SQL.

Transact-SQL¶

 CREATE OR ALTER FUNCTION CalculateAveragePrice(@pid INT)
RETURNS MONEY
AS
BEGIN
  DECLARE @average AS MONEY;
  SELECT @average = AVG(LISTPRICE) FROM Production.ProductListPriceHistory WHERE ProductID = @pid;
  RETURN @average;
END;
GO

CREATE OR ALTER PROCEDURE SetNewPrice @ProductID INT
AS
  DECLARE @averageHistoricalPrice MONEY;
  EXECUTE @averageHistoricalPrice = [dbo].Calculate_Average_Price @pid=@ProductID;
  UPDATE Production.ProductListPriceHistory SET ListPrice = @averageHistoricalPrice WHERE ProductID =  @ProductID AND EndDate IS NULL;
GO

EXECUTE Set_New_Price @ProductID = 707;
SELECT ListPrice FROM Production.ProductListPriceHistory WHERE ProductID = 707 AND EndDate IS NULL;

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ListPrice|
---------+
  34.0928|

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Snowflake Scripting¶

 CREATE OR REPLACE FUNCTION CalculateAveragePrice (PID INT)
RETURNS NUMBER(38, 4)
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
AS
$$
  WITH CTE1 AS
  (
    SELECT
      AVG(LISTPRICE) AS AVERAGE FROM
      Production.ProductListPriceHistory
    WHERE
      ProductID = PID
  )
  SELECT
    AVERAGE
  FROM
    CTE1
$$;

CREATE OR REPLACE PROCEDURE SetNewPrice (PRODUCTID INT)
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
  DECLARE
    AVERAGEHISTORICALPRICE NUMBER(38, 4);
  BEGIN
     
    CALL dbo.Calculate_Average_Price(:PRODUCTID);
    UPDATE Production.ProductListPriceHistory
      SET
        ListPrice = :AVERAGEHISTORICALPRICE
      WHERE
        ProductID = :PRODUCTID
        AND EndDate IS NULL;
  END;
$$;

CALL Set_New_Price(707);

SELECT
  ListPrice
FROM
  Production.ProductListPriceHistory
WHERE
  ProductID = 707 AND EndDate IS NULL;

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Unsupported Optional arguments¶

@return_status
;number
@module__name_v_ar
WITH RECOMPILE, WITH RESULT SETS NONE, WITH <result set definition>

Related EWIs¶

SSC-EWI-0030: The statement below has usages of dynamic SQL.

IF¶

Applies to

[x] SQL Server
[x] Azure Synapse Analytics

Description ¶

The IF clause allows an SQL statement or a block of statements to be conditionally executed as long as the Boolean expression is true; otherwise, the statements in the optional ELSE clause will be executed. Transact-SQL also supports embedding multiple IF… ELSE clauses in case multiple conditions are required, or the CASE clause can also be used.

For more information for Transact-SQL IF…ELSE, check here.

 IF Boolean_expression   
     { sql_statement | statement_block }   
[ ELSE   
     { sql_statement | statement_block } ]   

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Note: To define a statement block, use the control-of-flow keywords BEGIN and END.

Sample Source Patterns ¶

Transact-SQL¶

The following code refers to an IF… ELSE in Transact-SQL that conditions the variable @value to identify if it is less than 5, if it is between 5 and 10, or if it has any other value. Since @value is initialized as 7, the second condition must be true and the result must be 200.

 CREATE OR ALTER PROCEDURE IfElseDemoProcedure
AS
    DECLARE @value INT;
    SET @value = 7;

    IF @value < 5
        SET @value = 100;
    ELSE IF @value >= 5 AND @value < 10
        BEGIN
            SET @value = 300;
            SET @value = @value - 100;
        END;
    ELSE  
        SET @value = -1;


    RETURN @value
GO


DECLARE @result INT;
EXEC @result = IfElseDemoProcedure;
PRINT @result;

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 |result|
|------|
|200   |

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Snowflake Scripting ¶

Note

Notice that in Snowflake Scripting, the embedded IF… ELSE condition is called ELSEIF.

Besides, the Boolean condition is encapsulated in parentheses and the clause always ends with the END IF expression.

In addition, in Snowflake Scripting it is not necessary to use the BEGIN and END keywords to define a statement block, however it can be used if required.

 CREATE OR REPLACE PROCEDURE IfElseDemoProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
    DECLARE
        VALUE INT;
    BEGIN
         
        VALUE := 7;
        IF (:VALUE < 5) THEN
            VALUE := 100;
        ELSEIF (:VALUE >= 5 AND :VALUE < 10) THEN
            BEGIN
                VALUE := 300;
                VALUE := :VALUE - 100;
            END;
        ELSE
            VALUE := -1;
        END IF;
        RETURN :VALUE;
    END;
$$;

DECLARE
    RESULT INT;
BEGIN
    CALL IfElseDemoProcedure();
    !!!RESOLVE EWI!!! /*** SSC-EWI-0073 - PENDING FUNCTIONAL EQUIVALENCE REVIEW FOR 'Print' NODE ***/!!!
    PRINT @result;
END;

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|result|
|------|
|200   |

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IF statement outside routines (functions and procedures)¶

Unlike Transact-SQL, Snowflake does not support executing isolated statements like IF…ELSE outside routines like functions or procedures. For this scenario, the statement should be encapsulated in an anonymous block, as shown in the following example. You can read more about how to correctly return the output values in the SELECT section.

Transact-SQL¶

 DECLARE @maxWeight FLOAT, @productKey INTEGER  
SET @maxWeight = 100.00  
SET @productKey = 424  
IF @maxWeight <= 99  
    SELECT @productKey,  'This product is too heavy to ship and is only available for pickup.' 
ELSE  
    SELECT @productKey, 'This product is available for shipping or pickup.' 

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Snowflake Scripting

 DECLARE
    MAXWEIGHT FLOAT;
    PRODUCTKEY INTEGER;
    BlockResultSet1 VARCHAR;
    BlockResultSet2 VARCHAR;
    return_arr ARRAY := array_construct();
BEGIN
    MAXWEIGHT := 100.00;
    PRODUCTKEY := 424;
    IF (:MAXWEIGHT <= 99) THEN
        BlockResultSet1 := 'RESULTSET_' || REPLACE(UPPER(UUID_STRING()), '-', '_');
        CREATE OR REPLACE TEMPORARY TABLE IDENTIFIER(:BlockResultSet1) AS
            SELECT
                :PRODUCTKEY,  'This product is too heavy to ship and is only available for pickup.';
        return_arr := array_append(return_arr, :BlockResultSet1);
    ELSE
        BlockResultSet2 := 'RESULTSET_' || REPLACE(UPPER(UUID_STRING()), '-', '_');
        CREATE OR REPLACE TEMPORARY TABLE IDENTIFIER(:BlockResultSet2) AS
            SELECT
                :PRODUCTKEY, 'This product is available for shipping or pickup.';
        return_arr := array_append(return_arr, :BlockResultSet2);
    END IF;
    --** SSC-FDM-0020 - MULTIPLE RESULT SETS ARE RETURNED IN TEMPORARY TABLES **
    RETURN return_arr;
END;

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Known Issues¶

No issues were found.

Related EWIs¶

SSC-EWI-0073: Pending Functional Equivalence Review.
SSC-FDM-0020: Multiple result sets are returned in temporary tables.

LABEL and GOTO¶

Applies to

[x] SQL Server

Description¶

Snowflake SQL does not support GOTO LABEL statements. Currently, LABELS are commented and warning is added for all the occurrences.

Sample Source Patterns ¶

The following examples details the BEGIN and COMMIT transaction statements.

Transact-SQL ¶

 CREATE PROCEDURE GoToProcedure
AS
BEGIN
DECLARE @TotalMaarks INT
SET @TotalMaarks = 49;
IF @TotalMaarks >= 50
    GOTO Pass
IF @TotalMaarks < 50
    GOTO Fail
Pass:
    SELECT 1;
    RETURN 1;
Fail:
    SELECT 2;
    RETURN 2;
END

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Snowflake SQL ¶

 CREATE OR REPLACE PROCEDURE GoToProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
    DECLARE
        TOTALMAARKS INT;
    BEGIN
         
        TOTALMAARKS := 49;
        IF (:TOTALMAARKS >= 50) THEN
            !!!RESOLVE EWI!!! /*** SSC-EWI-0073 - PENDING FUNCTIONAL EQUIVALENCE REVIEW FOR 'GOTO' NODE ***/!!!
            GOTO Pass
        END IF;
        IF (:TOTALMAARKS < 50) THEN
            !!!RESOLVE EWI!!! /*** SSC-EWI-0073 - PENDING FUNCTIONAL EQUIVALENCE REVIEW FOR 'GOTO' NODE ***/!!!
            GOTO Fail
        END IF;
        !!!RESOLVE EWI!!! /*** SSC-EWI-TS0045 - LABELED STATEMENT IS NOT SUPPORTED IN SNOWFLAKE SCRIPTING ***/!!!
        Pass:
        SELECT 1;
        RETURN 1;

        !!!RESOLVE EWI!!! /*** SSC-EWI-TS0045 - LABELED STATEMENT IS NOT SUPPORTED IN SNOWFLAKE SCRIPTING ***/!!!
        Fail:
        SELECT 2;
        RETURN 2;

    END;
$$;

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LABEL and GOTO statement outside routines (functions and procedures)¶

Transact-SQL

 CREATE TABLE T12(COL1 INT);
GOTO SecondStat
FirstStat:
    INSERT INTO T12 VALUES (1);
SecondStat:
    INSERT INTO T12 VALUES (2);

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Snowflake Scripting

BEGIN
    CREATE OR REPLACE TABLE T12 (
        COL1 INT
    );
        !!!RESOLVE EWI!!! /*** SSC-EWI-0073 - PENDING FUNCTIONAL EQUIVALENCE REVIEW FOR 'Goto' NODE ***/!!!
        GOTO SecondStat;
        !!!RESOLVE EWI!!! /*** SSC-EWI-TS0045 - LABELED STATEMENT IS NOT SUPPORTED IN SNOWFLAKE SCRIPTING ***/!!!
        FirstStat:
    INSERT INTO T12 VALUES (1);

        !!!RESOLVE EWI!!! /*** SSC-EWI-TS0045 - LABELED STATEMENT IS NOT SUPPORTED IN SNOWFLAKE SCRIPTING ***/!!!
        SecondStat:
    INSERT INTO T12 VALUES (2);

END;

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Known Issues¶

No issues were found.

Related EWIs¶

SSC-EWI-TS0045: Labeled Statement is not supported in Snowflake Scripting.
SSC-EWI-0073: Pending Functional Equivalence Review.

OUTPUT PARAMETERS¶

Applies to

[x] SQL Server
[x] Azure Synapse Analytics

Note

Some parts in the output code are omitted for clarity reasons.

Description¶

An output parameter is a parameter whose value is passed out of the stored procedure, back to the calling SQL block. Since the output parameters are not supported by Snowflake Scripting, a solution has been implemented in order to emulate their functionality.

Sample Source Patterns¶

Single OUT parameter¶

The most basic scenario for OUT parameters is when the procedure only has one. In this case, we simply return the OUT parameter at the end of the procedure body.

The EXEC procedure has to be translated as well, for this a CALL is created, the parameters are passed without any modifier (“OUT” is removed), and subsequently, an assignment is done so the parameter is associated with it’s respective resulting value.

Transact-SQL¶

 -- Procedure with output parameter
CREATE PROCEDURE dbo.outmain
@name VARCHAR (255) OUTPUT
AS
SET @name = 'Jane';

-- Auxiliary procedure that calls the main procedure
CREATE PROCEDURE dbo.outaux
AS
DECLARE @name VARCHAR (255);
EXEC dbo.outmain
    @name = @name OUTPUT;

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Snowflake Scripting¶

 -- Procedure with output parameter
CREATE OR REPLACE PROCEDURE dbo.outmain (NAME STRING)
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
    BEGIN
        NAME := 'Jane';

        -- Auxiliary procedure that calls the main procedure
        !!!RESOLVE EWI!!! /*** SSC-EWI-0073 - PENDING FUNCTIONAL EQUIVALENCE REVIEW FOR 'CREATE PROCEDURE' NODE ***/!!!
        CREATE PROCEDURE dbo.outaux
AS
DECLARE @name VARCHAR (255);
EXEC dbo.outmain
    @name = @name OUTPUT;
        RETURN NAME;
    END;
$$;

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Multiple OUT parameters¶

When more than one OUT parameters are found, the RETURNS clause of the procedure changes to VARIANT. This is to accommodate the OBJECT_CONSTRUCT that is going to be used to store the values of the OUT parameters.

On top of that, a RETURN statement is added to the end of the procedure’s body. This is where the OBJECT_COSNTRUCT is created and all the OUT parameter values are stored within it. This object will then be used by the caller to assign the parameters value to the corresponding result.

Transact-SQL¶

 CREATE OR ALTER PROCEDURE basicProc (
    @col1 INT OUT,
    @col2 VARCHAR(10) OUT
) AS
BEGIN
    SET @col1 = 4;
    SET @col2 = 'test';
END;

CREATE OR ALTER PROCEDURE basicProcCall AS
BEGIN
    DECLARE @var1 INT = 0;
    DECLARE @var2 VARCHAR(10) = 'EMPTY';

    EXEC basicProc @var1 OUT, @var2 OUT;
    INSERT INTO TABLE1(col1, col2) VALUES (@var1, @var2);
END;

EXEC basicProcCall;

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Snowflake Scripting¶

 CREATE OR REPLACE PROCEDURE basicProc (COL1 INT, COL2 STRING)
RETURNS VARIANT
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
    BEGIN
        BEGIN
            COL1 := 4;
            COL2 := 'test';
        END;
        !!!RESOLVE EWI!!! /*** SSC-EWI-0073 - PENDING FUNCTIONAL EQUIVALENCE REVIEW FOR 'CREATE PROCEDURE' NODE ***/!!!
        CREATE OR ALTER PROCEDURE basicProcCall AS
BEGIN
    DECLARE @var1 INT = 0;
    DECLARE @var2 VARCHAR(10) = 'EMPTY';

    EXEC basicProc @var1 OUT, @var2 OUT;
    INSERT INTO TABLE1(col1, col2) VALUES (@var1, @var2);
END;

EXEC basicProcCall;
        RETURN OBJECT_CONSTRUCT('COL1', :COL1, 'COL2', :COL2);
    END;
$$;

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OUT parameters and return values¶

Transact-SQL allows procedures to have return values. When a procedure has both a return value and OUT parameter(s), a similar approach to the Multiple OUT parameters scenario is followed. The original return value is treated as an OUT parameter would be treated, so it’s stored within the OBJECT_CONSTRUCT and extracted inside the caller procedure.

Transact-SQL¶

 -- Procedure with multiple output parameters
CREATE PROCEDURE dbo.outmain
@name VARCHAR (255) OUTPUT
AS
SET @name = 'Jane';
RETURN 0;

-- Auxiliary procedure that calls the main procedure
CREATE PROCEDURE dbo.outaux
AS
DECLARE @name VARCHAR (255);
DECLARE @returnValue INT;
EXEC @returnValue = dbo.outmain
    @name = @name OUTPUT;

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Snowflake Scripting¶

 -- Procedure with multiple output parameters
CREATE OR REPLACE PROCEDURE dbo.outmain (NAME STRING)
RETURNS VARIANT
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
    BEGIN
        NAME := 'Jane';
        RETURN OBJECT_CONSTRUCT('SC_RET_VALUE', 0, 'NAME', :NAME);

        -- Auxiliary procedure that calls the main procedure
        !!!RESOLVE EWI!!! /*** SSC-EWI-0073 - PENDING FUNCTIONAL EQUIVALENCE REVIEW FOR 'CREATE PROCEDURE' NODE ***/!!!
        CREATE PROCEDURE dbo.outaux
AS
DECLARE @name VARCHAR (255);
DECLARE @returnValue INT;
EXEC @returnValue = dbo.outmain
    @name = @name OUTPUT;
    END;
$$;

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Customer data type OUT parameters¶

when the output parameter is a customer type, the process is similar to a regular data type.

Transact-SQL¶

 CREATE PROCEDURE procedure_udtype_out_params(
  @p_employee_id INT,
  @p_phone [dbo].[PhoneNumber] OUTPUT
) AS
BEGIN
  SELECT @p_phone = phone
  FROM employees
  WHERE employee_id = @p_employee_id;
END;

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Snowflake Scripting¶

 CREATE OR REPLACE PROCEDURE procedure_udtype_out_params (P_EMPLOYEE_ID INT, P_PHONE VARIANT /*** SSC-FDM-TS0015 - DATA TYPE DBO.PHONENUMBER IS NOT SUPPORTED IN SNOWFLAKE ***/)
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
  BEGIN
    SELECT
      phone
    INTO
      :P_PHONE
    FROM
      employees
    WHERE
      employee_id = :P_EMPLOYEE_ID;
    RETURN P_PHONE;
  END;
$$;

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Known Issues ¶

No issues were found.

Related EWIs¶

SSC-EWI-0073: Pending Functional Equivalence Review.
SSC-FDM-TS0015: Data type is not supported in Snowflake.

SET¶

Applies to

[x] SQL Server
[x] Azure Synapse Analytics

Description¶

Sets the specified local variable, previously created by using the DECLARE @local_variable statement, to the specified value. For more information for Transact-SQL SET, check here.

There are four SET cases that are the following:

 SET   
{ @local_variable  
    [ . { property_name | field_name } ] = { expression | udt_name { . | :: } method_name }  
}  
|  
{ @SQLCLR_local_variable.mutator_method  
}  
|  
{ @local_variable  
    {+= | -= | *= | /= | %= | &= | ^= | |= } expression  
}  
|   
  { @cursor_variable =   
    { @cursor_variable | cursor_name   
    | { CURSOR [ FORWARD_ONLY | SCROLL ]   
        [ STATIC | KEYSET | DYNAMIC | FAST_FORWARD ]   
        [ READ_ONLY | SCROLL_LOCKS | OPTIMISTIC ]   
        [ TYPE_WARNING ]   
    FOR select_statement   
        [ FOR { READ ONLY | UPDATE [ OF column_name [ ,...n ] ] } ]   
      }   
    }  
}

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Sample Source Patterns ¶

Transact-SQL¶

 CREATE OR ALTER PROCEDURE SetProcedure
AS
    DECLARE @MyCounter INT;  
    DECLARE @FloatCounter FLOAT; 
	
    --Numerical operators
    SET @MyCounter = 3;  
    SET @MyCounter += 1;  --@MyCounter has 4
    SET @MyCounter -= 1;  --@MyCounter has 3
    SET @MyCounter *= 2;  --@MyCounter has 6
	
    SET @MyCounter /= 3;  --@MyCounter has 2
    SET @MyCounter = 6;  
    SET @MyCounter /= 5;  --@MyCounter has 1
    SET @MyCounter = 6;   
    SET @MyCounter /= 7;  --@MyCounter has 0
    SET @FloatCounter = 10;
    SET @FloatCounter /= 4;  --@FloatCounter has 2.5
    
    SET @MyCounter = 6;   
    SET @MyCounter %= 4;  --@MyCounter has 2
	
    --Logical operators
    SET @MyCounter &= 3;  --@MyCounter has 2
    SET @MyCounter ^= 2;  --@MyCounter has 0
    SET @MyCounter |= 0;  --@MyCounter has 0
		
    RETURN @MyCounter;
GO

DECLARE @result INT;
EXEC @result = SetProcedure;
PRINT @result;

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 CREATE TABLE vEmployee (
    PersonID int,
    LastName varchar(255),
    FirstName varchar(255)
);

CREATE OR ALTER PROCEDURE SetCursor
AS
    DECLARE @CursorVar CURSOR; 
	
    SET @CursorVar = CURSOR SCROLL DYNAMIC  
        FOR  
	SELECT LastName, FirstName  
	FROM vEmployee  
	WHERE LastName like 'B%'; 
GO	

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|Result   |
|---------|
|0        |

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Snowflake Scripting ¶

 CREATE OR REPLACE PROCEDURE SetProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
    DECLARE
        MYCOUNTER INT;
        FLOATCOUNTER FLOAT;
    BEGIN
         
         

        --Numerical operators
        MYCOUNTER := 3;
        MYCOUNTER := MYCOUNTER + 1;  --@MyCounter has 4

        MYCOUNTER := MYCOUNTER - 1;  --@MyCounter has 3

        MYCOUNTER := MYCOUNTER * 2;  --@MyCounter has 6

        MYCOUNTER := TRUNC(MYCOUNTER / 3);  --@MyCounter has 2

        MYCOUNTER := 6;
        MYCOUNTER := TRUNC(MYCOUNTER / 5);  --@MyCounter has 1

        MYCOUNTER := 6;
        MYCOUNTER := TRUNC(MYCOUNTER / 7);  --@MyCounter has 0

        FLOATCOUNTER := 10;
        FLOATCOUNTER := FLOATCOUNTER / 4;  --@FloatCounter has 2.5

        MYCOUNTER := 6;
        MYCOUNTER := MYCOUNTER % 4;  --@MyCounter has 2

    --Logical operators
        MYCOUNTER := BITAND(MYCOUNTER, 3);  --@MyCounter has 2

        MYCOUNTER := BITXOR(MYCOUNTER, 2);  --@MyCounter has 0

        MYCOUNTER := BITOR(MYCOUNTER, 0);  --@MyCounter has 0

        RETURN :MYCOUNTER;
    END;
$$;

DECLARE
    RESULT INT;
BEGIN
    CALL SetProcedure();
    !!!RESOLVE EWI!!! /*** SSC-EWI-0073 - PENDING FUNCTIONAL EQUIVALENCE REVIEW FOR 'Print' NODE ***/!!!
    PRINT @result;
END;

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 CREATE OR REPLACE TABLE vEmployee (
	PersonID INT,
	LastName VARCHAR(255),
	FirstName VARCHAR(255)
)
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
;

CREATE OR REPLACE PROCEDURE SetCursor ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
	DECLARE
		!!!RESOLVE EWI!!! /*** SSC-EWI-TS0037 - SNOWFLAKE SCRIPTING CURSORS ARE NON-SCROLLABLE, ONLY FETCH NEXT IS SUPPORTED ***/!!!
		--** SSC-FDM-TS0013 - SNOWFLAKE SCRIPTING CURSOR ROWS ARE NOT MODIFIABLE **
		CURSORVAR CURSOR
		FOR
			SELECT LastName, FirstName
			FROM vEmployee
			WHERE LastName like 'B%';
	BEGIN
		 
		 
		RETURN '';
	END;
$$;

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|Result   |
|---------|
|0        |

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SET statement outside routines (functions and procedures)¶

Unlike Transact-SQL, Snowflake does not support executing isolated statements like SET outside routines like functions or procedures. For this scenario, the statement should be encapsulated in an anonymous block, as shown in the following examples. This statement is usually used after a DECLARE STATEMENT.

Transact-SQL¶

 DECLARE @Group nvarchar(50), @Sales MONEY;
SET @Group = N'North America';
SET @Sales = 2000000;

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Snowflake Scripting

 DECLARE
_GROUP VARCHAR(50);
SALES NUMBER(38, 4);
BEGIN
_GROUP := 'North America';
SALES := 2000000;
END;

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If there is a scenario with only SET statements, the DECLARE block is not necessary. Probably this scenario will produce runtime errors if there is an attempt of setting a value to a variable that is not declared.

Transact-SQL¶

 SET @Group = N'North America';

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Snowflake Scripting

 BEGIN
_GROUP := 'North America';
END;

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Known Issues¶

1. SET of a local variable with property name¶

This type of set is not currently supported by Snowflake scripting.

 // TSQL custom data type with properties example 
DECLARE @p Point;  
SET @p.X = @p.X + 1.1;  

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2. SET of a local variable with mutator method¶

This type of set is not currently supported by Snowflake scripting.

 // TSQL custom data type with mutator method
SET @p.SetXY(22, 23);   

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Related EWIs¶

SSC-EWI-TS0037: Snowflake Scripting Cursors are non-scrollable.
SSC-EWI-0073: Pending Functional Equivalence Review.
SSC-FDM-TS0013: Snowflake Scripting cursor rows are not modifiable.

TRY CATCH¶

Applies to

[x] SQL Server
[x] Azure Synapse Analytics

Description¶

Implements error handling for Transact SQL. A group of Transact-SQL statements can be enclosed in a TRY block. If an error occurs in the TRY block, control is usually passed to another group of statements that is enclosed in a CATCH block.

Sample Source Patterns ¶

The following example details the transformation for TRY CATCH inside procedures.

Transact-SQL ¶

 CREATE PROCEDURE ERROR_HANDLING_PROC
AS
BEGIN
    BEGIN TRY  
        -- Generate divide-by-zero error.  
        SELECT 1/0;  
    END TRY  
    BEGIN CATCH  
        -- Execute error retrieval routine.  
        SELECT 'error';
    END CATCH;   
END;

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|error    |

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Snowflake SQL ¶

 CREATE OR REPLACE PROCEDURE ERROR_HANDLING_PROC ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
    BEGIN
        BEGIN
            -- Generate divide-by-zero error.  
            SELECT
                TRUNC( 1/0);
        EXCEPTION
            WHEN OTHER THEN
                -- Execute error retrieval routine.  
                SELECT 'error';
        END;
    END;
$$;

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|error    |

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Try catch outside routines (functions and procedures)¶

Transact-SQL

 BEGIN TRY  
    SELECT 1/0;  
END TRY  
BEGIN CATCH  
    SELECT 'error';
END CATCH;

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Snowflake Scripting

 DECLARE
    BlockResultSet1 VARCHAR;
    BlockResultSet2 VARCHAR;
    return_arr ARRAY := array_construct();
BEGIN
    BEGIN
        BlockResultSet1 := 'RESULTSET_' || REPLACE(UPPER(UUID_STRING()), '-', '_');
        CREATE OR REPLACE TEMPORARY TABLE IDENTIFIER(:BlockResultSet1) AS
            SELECT
                TRUNC( 1/0);
        return_arr := array_append(return_arr, :BlockResultSet1);
    EXCEPTION
        WHEN OTHER THEN
            BlockResultSet2 := 'RESULTSET_' || REPLACE(UPPER(UUID_STRING()), '-', '_');
            CREATE OR REPLACE TEMPORARY TABLE IDENTIFIER(:BlockResultSet2) AS
                SELECT 'error';
            return_arr := array_append(return_arr, :BlockResultSet2);
    END;
    --** SSC-FDM-0020 - MULTIPLE RESULT SETS ARE RETURNED IN TEMPORARY TABLES **
    RETURN return_arr;
END;

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Known Issues¶

No issues were found.

Related EWIs¶

SSC-FDM-0020: Multiple result sets are returned in temporary tables.

WHILE¶

Applies to

[x] SQL Server
[x] Azure Synapse Analytics

Description ¶

The While statement allows an SQL statement or a block of statements to be repeatedly executed as long as the specified condition is true. The execution of statements in the WHILE loop can be controlled from inside the loop with the BREAK and CONTINUE keywords.

For more information for Transact-SQL While, check here.

 WHILE Boolean_expression   
     { sql_statement | statement_block | BREAK | CONTINUE }

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Note: To define a statement block, use the control-of-flow keywords BEGIN and END.

Sample Source Patterns ¶

Basic source pattern code¶

Transact-SQL ¶

The following code refers to a While Loop in Transact-SQL that iterates the @Iteration variable and controls the flow of the loop to terminate when the value of @Iteration equals 10.

Note

Statements after the CONTINUE keyword will not be executed.

 CREATE OR ALTER PROCEDURE WhileDemoProcedure
AS
    DECLARE @iteration INT;
    SET @iteration = 1;
    
    WHILE @iteration < 100
    BEGIN
        IF @iteration = 10
            BREAK;
        ELSE
            BEGIN
                SET @iteration = @iteration + 1;
                CONTINUE;
                SET @iteration = 2 * @iteration;
            END;
    END;
    RETURN @iteration;
GO



DECLARE @result INT;
EXEC @result = WhileDemoProcedure;
PRINT @result;

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|iteration|
|---------|
|10       |

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Snowflake Scripting ¶

Note

As well as Transact-SQL, in Snowflake Scripting the statements after the CONTINUE keyword will not be executed.

Notice that in Snowflake Scripting it is not necessary to use the BEGIN and END keywords to define a statement block, however it can be used if required.

CREATE OR REPLACE PROCEDURE WhileDemoProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
    DECLARE
        ITERATION INT;
    BEGIN
         
        ITERATION := 1;
        WHILE (:ITERATION &#x3C; 100) LOOP
            IF (:ITERATION = 10) THEN
                BREAK;
            ELSE
                BEGIN
                    ITERATION := :ITERATION + 1;
                    CONTINUE;
                    ITERATION := 2 * :ITERATION;
                END;
            END IF;
        END LOOP;
        RETURN :ITERATION;
    END;
$$;

DECLARE
    RESULT INT;
BEGIN
    CALL WhileDemoProcedure();
    !!!RESOLVE EWI!!! /*** SSC-EWI-0073 - PENDING FUNCTIONAL EQUIVALENCE REVIEW FOR 'Print' NODE ***/!!!
    PRINT @result;
END;

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Snowflake Scripting allows to use LOOP keyword instead of DO and the END LOOP expression instead of END WHILE .

 WHILE (Boolean_expression) LOOP
    -- statement or statement block
END LOOP;

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|Iteration|
|---------|
|10       |

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While with empty body Source Pattern¶

Transact-SQL ¶

Note

Please note this example was written while the IF ELSE statement was not supported, the differences in the results should disappear when support for the statement is implemented.

 CREATE OR ALTER PROCEDURE WhileEmptyBodyProc
AS
BEGIN
    DECLARE @MyVar INT;
    SET @MyVar = 1;
    WHILE (@MyVar < 100)
        BEGIN
            IF @MyVar < 50
                SET @MyVar *= 5;
            ELSE
                SET @MyVar *= 3;
        END;
    RETURN @MyVar;
END;

DECLARE @result INT;
EXEC @result = WhileEmptyBodyProc;
PRINT @result;

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|result|
|------|
|125   |

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Snowflake Scripting¶

This statement can not have an empty body in Snowflake Scripting, to solve this cases a default BREAK statement is added when an empty body is detected.

 CREATE OR REPLACE PROCEDURE WhileEmptyBodyProc ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"transact"}}'
EXECUTE AS CALLER
AS
$$
    DECLARE
        MYVAR INT;
        RESULT INT;
    BEGIN
        BEGIN
             
            MYVAR := 1;
            WHILE (:MYVAR < 100) LOOP
                IF (:MYVAR < 50) THEN
                    MYVAR := MYVAR * 5;
                ELSE
                    MYVAR := MYVAR * 3;
                END IF;
            END LOOP;
            RETURN :MYVAR;
        END;
         
        CALL WhileEmptyBodyProc();
        !!!RESOLVE EWI!!! /*** SSC-EWI-0073 - PENDING FUNCTIONAL EQUIVALENCE REVIEW FOR 'PRINT' NODE ***/!!!
        PRINT @result;
    END;
$$;

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|result|
|------|
|1     |

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WHILE statement outside routines (functions and procedures)¶

Unlike Transact-SQL, Snowflake does not support executing isolated statements like WHILE outside routines like functions or procedures. For this scenario, the statement should be encapsulated in an anonymous block, as shown in the following example.

Transact-SQL ¶

 DECLARE @iteration INT;
SET @iteration = 1;
 
WHILE @iteration < 100
BEGIN
    IF @iteration = 10
        BREAK;
    ELSE
        BEGIN
            SET @iteration = @iteration + 1;
            CONTINUE;
            SET @iteration = 2 * @iteration;
        END;
    END;

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Snowflake Scripting

 DECLARE
    ITERATION INT;
BEGIN
    ITERATION := 1;
    WHILE (:ITERATION < 100) LOOP
        IF (:ITERATION = 10) THEN
            BREAK;
        ELSE
            BEGIN
                ITERATION := :ITERATION + 1;
                CONTINUE;
                ITERATION := 2 * :ITERATION;
            END;
        END IF;
    END LOOP;
END;

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Known Issues¶

No issues were found.

Related EWIs¶

SSC-EWI-0073: Pending Functional Equivalence Review.