SnowConvert AI -Sybase IQ - SELECT

Description

Récupère des informations à partir de la base de données. (Référence de langage Sybase SQL).

Avertissement

Cette syntaxe est partiellement prise en charge par Snowflake.

Grammar Syntax

 SELECT 
[ ALL | DISTINCT ] 
[ row-limitation-option1 ] 
   	select-list
   … 	[ INTO { host-variable-list | variable-list | table-name } ]
   … 	[ INTO LOCAL TEMPORARY TABLE { table-name } ]
   … 	[ FROM table-list ]
   … 	[ WHERE search-condition ]
   … 	[ GROUP BY [ expression [, ...]
         | ROLLUP ( expression [, ...] )
         | CUBE ( expression [, ...] ) ] ] 
   … 	[ HAVING search-condition ]
   … 	[ ORDER BY { expression | integer } [ ASC | DESC ] [, ...] ]
   | 	[ FOR JSON json-mode ] 
   … [ row-limitation-option ]

select-list:
   { column-name
   | expression [ [ AS ] alias-name ]
   | * 
   }

row-limitation-option1:
   FIRST 
   | TOP {ALL | limit-expression} [START AT startat-expression ]
  
limit-expression:
    simple-expression
  
startat-expression:
    simple-expression

row-limitation-option2:
   LIMIT { [ offset-expression, ] limit-expression 
   | limit-expression OFFSET offset-expression }

offset-expression:
   simple-expression

simple-expression:
   integer
   | variable
   | ( simple-expression )
   | ( simple-expression { + | - | * } simple-expression )


..FROM <table-expression> [,...]

<table-expression> ::=
   <table-name>
   | <view-name>
   | <procedure-name>
   | <common-table-expression>
   | ( <subquery> ) [ [ AS ] <derived-table-name> ( <column_name, ...>) ] ]
   | <derived-table>
   | <join-expression> 
   | ( <table-expression> , ... )
   | <openstring-expression>
   | <apply-expression>
   | <contains-expression>
   | <dml-derived-table>

<table-name> ::=
   [ <userid>.] <table-name> ]
   [ [ AS ] <correlation-name> ]
   [ FORCE INDEX ( <index-name> ) ]

<view-name> ::=
   [ <userid>.]<view-name> [ [ AS ] <correlation-name> ]

<procedure-name> ::=
   [  <owner>, ] <procedure-name> ([ <parameter>, ...])
   [  WITH(<column-name datatype>, )]
   [ [ AS ] <correlation-name> ]

<parameter> ::=
   <scalar-expression> | <table-parameter>

<table-parameter> ::= 
   TABLE (<select-statement)> [ OVER ( <table-parameter-over> )]

<table-parameter-over> ::=
   [ PARTITION BY {ANY
   | NONE|< table-expression> } ] 
   [ ORDER BY { <expression> | <integer> } 
   [ ASC | DESC ] [, ...] ]

<derived-table> ::=
   ( <select-statement> ) 
   	[ AS ] <correlation-name> [ ( <column-name>, ... ) ]

<join-expression> ::=
   <table-expression> <join-operator> <table-expression>
   	[ ON <join-condition> ]

<join-operator> ::=
   [ KEY | NATURAL ] [ <join-type> ] JOIN | CROSS JOIN

<join-type> ::=
   INNER
     | LEFT [ OUTER ]
     | RIGHT [ OUTER ]
     | FULL [ OUTER ]

<openstring-expression> ::=
   OPENSTRING ( { FILE | VALUE } <string-expression> )
     WITH ( <rowset-schema> ) 
   	[ OPTION ( <scan-option> ...  ) ]
   	[ AS ] <correlation-name>

<apply-expression> ::=
   <table-expression> { CROSS | OUTER } APPLY <table-expression>

<contains-expression> ::=
   { <table-name>  | <view-name> } CONTAINS 
   ( <column-name> [,...], <contains-query> ) 
   [ [ AS ] <score-correlation-name> ]

<rowset-schema> ::=
   <column-schema-list>
	   | TABLE [<owner>.]<table-name> [ ( <column-list> ) ]

<column-schema-list> ::=
   { <column-name user-or-base-type> |  filler( ) } [ , ... ]

<column-list> ::=
   { <column-name> | filler( ) } [ , ... ]

<scan-option> ::=
   BYTE ORDER MARK { ON | OFF }
   | COMMENTS INTRODUCED BY <comment-prefix>
   | DELIMITED BY <string>
   | ENCODING <encoding>
   | ESCAPE CHARACTER <character>
   | ESCAPES { ON | OFF }
   | FORMAT { TEXT  | BCP  }
   | HEXADECIMAL { ON | OFF }
   | QUOTE <string>
   | QUOTES { ON | OFF }
   | ROW DELIMITED BY string
   | SKIP <integer>
   | STRIP { ON | OFF | LTRIM | RTRIM | BOTH }

<contains-query> ::= <string>

<dml-derived-table> ::=
   ( <dml-statement>  ) REFERENCING ( [ <table-version-names>  | NONE ] )

<dml-statement> ::=
   <insert-statement> 
   <update-statement>
   <delete-statement>

<table-version-names> ::=
   OLD [ AS ] <correlation-name> [ FINAL [ AS ] <correlation-name> ]
     | FINAL [ AS ] <correlation-name>

Modèles d’échantillons de sources

Limitation de ligne

Sybase allows row limitation in a query by using the TOP clause with an optional START AT. Snowflake does not support this syntax but it can be transformed as shown below to achieve the same functionality.

Code d’entrée :

Sybase
 SELECT
TOP 10 START AT 2
COL1 
FROM TABLE1;

SELECT
FIRST
COL1 
FROM TABLE1;

SELECT
COL1 
FROM TABLE1
LIMIT 2, 1;

SELECT
COL1 
FROM TABLE1
LIMIT 1 OFFSET 2;

Code de sortie :

Snowflake
 SELECT
COL1
FROM
TABLE1
LIMIT 10 OFFSET 2;

SELECT
TOP 1
COL1
FROM
TABLE1;

SELECT
COL1
FROM
TABLE1
LIMIT 1 OFFSET 2;

SELECT
COL1
FROM
TABLE1
LIMIT 1 OFFSET 2;

Dans la clause

In Sybase, a table can be defined by selecting multiple rows and defining a name to store the data retrieved. Snowflake does not support this behavior but can be emulated by doing a CREATE TABLE AS.

Code d’entrée :

Sybase
 SELECT
* INTO mynewtable
FROM TABLE1;

SELECT
* INTO LOCAL TEMPORARY TABLE mynewtable
FROM TABLE1;

SELECT
* INTO #mynewtable
FROM TABLE1;

Code de sortie :

Snowflake
 CREATE OR REPLACE TABLE mynewtable AS
SELECT
*
FROM
TABLE1;

CREATE OR REPLACE TEMPORARY TABLE mynewtable AS
SELECT
*
FROM
TABLE1;

CREATE OR REPLACE TEMPORARY TABLE T_mynewtable AS
SELECT
*
FROM
TABLE1;

Index de force

Snowflake ne contient pas d’index pour l’optimisation des requêtes.

Code d’entrée :

Sybase
 SELECT * FROM MyTable FORCE INDEX (MyIndex);

Code de sortie :

Snowflake
 SELECT
*
FROM
MyTable
--        --** SSC-FDM-SY0002 - FORCE INDEX IS NOT SUPPORTED IN SNOWFLAKE **
--        FORCE INDEX (MyIndex)
                             ;

TABLE FUNCTIONS

Snowflake permet d’appeler une procédure stockée (lorsque la procédure répond à certaines limites) ou une fonction de valeur de table dans une clause FROM, mais RESULTSETS et le fenêtrage ne peuvent pas être utilisés comme paramètres.

Code d’entrée :

Sybase
 SELECT * FROM 
MyProcedure(TABLE (SELECT * FROM TABLE1));

SELECT * FROM MyProcedure(1, 'test');

SELECT * FROM 
MyProcedure(
TABLE (SELECT * FROM TABLE1) 
OVER (PARTITION BY Col1 ORDER BY Col2 DESC));

SELECT * FROM 
MyProcedure(
TABLE (SELECT * FROM AnotherTable) );

Code de sortie :

Snowflake
 SELECT
*
FROM
TABLE(MyProcedure(
                  !!!RESOLVE EWI!!! /*** SSC-EWI-SY0004 - UNSUPPORTED SYNTAX TABLE FUNCTION CAN'T RECEIVE A QUERY AS PARAMETER ***/!!!TABLE (SELECT * FROM TABLE1)));

SELECT
*
FROM
TABLE(MyProcedure(1, 'test'));


SELECT
*
FROM
TABLE(MyProcedure(
!!!RESOLVE EWI!!! /*** SSC-EWI-SY0004 - UNSUPPORTED SYNTAX TABLE FUNCTION CAN'T RECEIVE A QUERY AS PARAMETER ***/!!!
TABLE (SELECT * FROM TABLE1)
!!!RESOLVE EWI!!! /*** SSC-EWI-SY0005 - UNSUPPORTED SYNTAX TABLE FUNCTION CAN'T BE USED WITH OVER EXPRESSION ***/!!!
OVER (PARTITION BY Col1 ORDER BY Col2 DESC)));


SELECT
*
FROM
TABLE(MyProcedure(
!!!RESOLVE EWI!!! /*** SSC-EWI-SY0004 - UNSUPPORTED SYNTAX TABLE FUNCTION CAN'T RECEIVE A QUERY AS PARAMETER ***/!!!
TABLE (SELECT * FROM AnotherTable) ));

OPEN STRING

Snowflake ne prend pas en charge la fonctionnalité OPENSTRING.

Code d’entrée :

Sybase
 -- Openstring from file
SELECT * FROM 
OPENSTRING (FILE '/path/to/file.txt') 
WITH (Col1 INT, Col2 VARCHAR(20)) AS OS;

-- Openstring from value
SELECT * FROM 
OPENSTRING (VALUE '1,test') 
WITH (Col1 INT, Col2 VARCHAR(20)) AS OS;

-- Openstring with options
SELECT * FROM 
OPENSTRING (FILE '/path/to/file.csv') 
WITH (Col1 INT, Col2 VARCHAR(20)) 
OPTION (DELIMITED BY ',' QUOTE '"') AS OS;

Code de sortie :

Snowflake
 -- Openstring from file
SELECT
*
FROM
!!!RESOLVE EWI!!! /*** SSC-EWI-SY0006 - OPEN STRING IS NOT SUPPORTED IN SNOWFLAKE ***/!!!
OPENSTRING (FILE '/path/to/file.txt')
WITH (Col1 INT, Col2 VARCHAR(20)) AS OS;

-- Openstring from value
SELECT
*
FROM
!!!RESOLVE EWI!!! /*** SSC-EWI-SY0006 - OPEN STRING IS NOT SUPPORTED IN SNOWFLAKE ***/!!!
OPENSTRING (VALUE '1,test')
WITH (Col1 INT, Col2 VARCHAR(20)) AS OS;

-- Openstring with options
SELECT
*
FROM
!!!RESOLVE EWI!!! /*** SSC-EWI-SY0006 - OPEN STRING IS NOT SUPPORTED IN SNOWFLAKE ***/!!!
OPENSTRING (FILE '/path/to/file.csv')
WITH (Col1 INT, Col2 VARCHAR(20))
OPTION (DELIMITED BY ',' QUOTE '"') AS OS;

Table dérivée DML

Dans Sybase, lors de l’exécution, l’instruction DML spécifiée dans la table dérivée dml est exécutée en premier, et les lignes affectées par ce DML se matérialisent dans une table temporaire dont les colonnes sont décrites par la clause REFERENCING. La table temporaire représente le jeu de résultats de la table dérivée-dml. Snowflake ne prend pas en charge ce comportement.

Code d’entrée :

Sybase
 -- DML derived table with insert
SELECT * FROM (INSERT INTO TargetTable (Col1, Col2) VALUES (1, 'test')) REFERENCING (FINAL AS F);

-- DML derived table with update
SELECT * FROM (UPDATE TargetTable SET Col2 = 'updated' WHERE Col1 = 1) REFERENCING (OLD AS O FINAL AS F);

-- DML derived table with delete
SELECT * FROM (DELETE FROM TargetTable WHERE Col1 = 1) REFERENCING (OLD AS O);

Code de sortie :

Snowflake
 -- DML derived table with insert
SELECT
*
FROM
!!!RESOLVE EWI!!! /*** SSC-EWI-SY0007 - DML DERIVED TABLE NOT SUPPORTED IN SNOWFLAKE ***/!!! (INSERT INTO TargetTable (Col1, Col2) VALUES (1, 'test')) REFERENCING (FINAL AS F);

-- DML derived table with update
SELECT
*
FROM
!!!RESOLVE EWI!!! /*** SSC-EWI-SY0007 - DML DERIVED TABLE NOT SUPPORTED IN SNOWFLAKE ***/!!! (UPDATE TargetTable SET Col2 = 'updated' WHERE Col1 = 1) REFERENCING (OLD AS O FINAL AS F);

-- DML derived table with delete
SELECT
*
FROM
!!!RESOLVE EWI!!! /*** SSC-EWI-SY0007 - DML DERIVED TABLE NOT SUPPORTED IN SNOWFLAKE ***/!!! (DELETE FROM TargetTable WHERE Col1 = 1) REFERENCING (OLD AS O);

KEY JOIN

Snowflake does not support KEY join but when the ON CLAUSE is defined in the query the KEY keyword is removed; otherwise, an EWI is inserted.

Code d’entrée :

Sybase
 SELECT * FROM Table1 KEY JOIN Table2;
SELECT * FROM Table1 KEY JOIN Table2 ON Table1.ID = Table2.ID;

Code de sortie :

Snowflake
 SELECT
*
FROM
Table1
!!!RESOLVE EWI!!! /*** SSC-EWI-SY0009 - KEY JOIN NOT SUPPORTED IN SNOWFLAKE ***/!!!
KEY JOIN
Table2;

SELECT
*
FROM
Table1
JOIN
Table2
ON Table1.ID = Table2.ID;

OUTER-CROSS APPLY

Snowflake transforme la clause CROSS APPLY en LEFT OUTER JOIN et OUTER APPLY en INNER JOIN.

Code d’entrée :

Sybase
 -- Apply cross apply
SELECT * FROM Table1 CROSS APPLY (SELECT Col2 FROM Table2 WHERE Table1.ID = Table2.ID) AS AP;

-- Apply outer apply
SELECT * FROM Table1 OUTER APPLY (SELECT Col2 FROM Table2 WHERE Table1.ID = Table2.ID) AS AP;

Code de sortie :

Snowflake
 -- Apply cross apply
SELECT
    *
FROM
    Table1
    LEFT OUTER JOIN (
        SELECT
            Col2
        FROM
            Table2
        WHERE
            Table1.ID = Table2.ID
    ) AS AP;

-- Apply outer apply
SELECT
    *
FROM
    Table1
    INNER JOIN LATERAL (
        SELECT
            Col2
        FROM
            Table2
        WHERE
            Table1.ID = Table2.ID
    ) AS AP;

Clause CONTAINS

Dans Sybase, la clause CONTAINS suit un nom de table pour filtrer la table et renvoyer uniquement les lignes correspondant à la requête en texte intégral spécifiée avec ’contient-requête’. Chaque ligne correspondante de la table est renvoyée avec une colonne de score à laquelle il est possible de faire référence à l’aide de ’nom-corrélation-score’. Snowflake ne prend pas en charge ce comportement.

Code d’entrée :

Sybase
 -- Contains clause
SELECT * FROM MyTable CONTAINS (TextColumn, 'search term') AS Score;

-- Contains clause with multiple columns.
SELECT * FROM MyTable CONTAINS (TextColumn,TextColumn2, 'search term') AS Score;

Code de sortie :

Snowflake
 -- Contains clause
SELECT
*
FROM
MyTable
        !!!RESOLVE EWI!!! /*** SSC-EWI-SY0008 - CONTAINS CLAUSE NOT SUPPORTED IN SNOWFLAKE ***/!!!
        CONTAINS (TextColumn, 'search term') AS Score;

-- Contains clause with multiple columns.
SELECT
*
FROM
MyTable
        !!!RESOLVE EWI!!! /*** SSC-EWI-SY0008 - CONTAINS CLAUSE NOT SUPPORTED IN SNOWFLAKE ***/!!!
        CONTAINS (TextColumn,TextColumn2, 'search term') AS Score;