SnowConvert AI - Oracle - Selecionar¶

In this section you could find information about the select query syntax and its conversions.

Nota

Algumas partes dos códigos de saída foram omitidas por motivos de clareza.

Conversão geral de Select¶

Select simples¶

Oracle:¶

select * from table1;
select col1 from schema1.table1;

Snowflake:¶

select * from
table1;

select col1 from
schema1.table1;

Cláusula Where¶

Oracle:¶

select col1 from schema1.table1 WHERE col1 = 1 and id > 0 or id < 1;

Snowflake:¶

select col1 from
schema1.table1
WHERE col1 = 1 and id > 0 or id < 1;

Cláusula Order by¶

Oracle:¶

select col1 from schema1.table1 order by id ASC;

Snowflake:¶

select col1 from
schema1.table1
order by id ASC;

Group by¶

Oracle:¶

select col1 from schema1.table1 GROUP BY id;

Snowflake:¶

select col1 from
schema1.table1
GROUP BY id;

Cláusula Model¶

A cláusula Model ainda não é compatível.

Cláusula Row Limiting¶

Oracle:¶

-- Using ONLY
select * from TableFetch1 FETCH FIRST 2 ROWS ONLY;
select * from TableFetch1 FETCH FIRST 20 percent ROWS ONLY;
select * from TableFetch1 order by col1 FETCH FIRST 2 ROWS with ties;
select * from TableFetch1 order by col1 FETCH FIRST 20 percent ROWS with ties;

-- Using OFFSET clause
select * from TableFetch1 offset 2 rows FETCH FIRST 2 ROWS ONLY;
select * from TableFetch1 offset 2 rows FETCH FIRST 60 percent rows ONLY;
select * from TableFetch1 
order by col1 offset 2 rows FETCH NEXT 2 ROWs with ties;
select * from TableFetch1 
order by col1 offset 2 rows FETCH FIRST 60 percent ROWs with ties;

-- Using WITH TIES clause
select * from TableFetch1 FETCH FIRST 2 ROWS with ties;
select * from TableFetch1 FETCH FIRST 20 percent ROWS with ties;
select * from TableFetch1 offset 2 rows FETCH NEXT 2 ROWs with ties;
select * from TableFetch1 offset 2 rows FETCH FIRST 60 percent ROWs with ties;

-- Using ORDER BY clause
select * from TableFetch1 order by col1 FETCH FIRST 2 ROWS ONLY;
select * from TableFetch1 order by col1 FETCH FIRST 20 percent ROWS ONLY;
select * from TableFetch1 order by col1 offset 2 rows FETCH FIRST 2 ROWS ONLY;
select * from TableFetch1 
order by col1 offset 2 rows FETCH FIRST 60 percent ROWS ONLY;

select * from TableFetch1 FETCH FIRST ROWS ONLY;

select * from TableFetch1 offset 2 rows;

Snowflake:¶

-- Using ONLY
select * from
TableFetch1
FETCH FIRST 2 ROWS ONLY;

select * from
TableFetch1
QUALIFY
(ROW_NUMBER() OVER (
ORDER BY
NULL) - 1) / COUNT(*) OVER () < 20 / 100;

select * from
TableFetch1
QUALIFY
RANK() OVER (
order by col1) <= 2;

select * from
TableFetch1
QUALIFY
(RANK() OVER (
order by col1) - 1) / COUNT(*) OVER () < 20 / 100;

-- Using OFFSET clause
select * from
TableFetch1
offset 2 rows FETCH FIRST 2 ROWS ONLY;

select * from
TableFetch1
QUALIFY
(ROW_NUMBER() OVER (
ORDER BY
NULL) - 1 - 2) / COUNT(*) OVER () < 60 / 100
LIMIT NULL OFFSET 2;

select * from
TableFetch1
QUALIFY
RANK() OVER (
order by col1) - 2 <= 2
LIMIT NULL OFFSET 2;

select * from
TableFetch1
QUALIFY
(RANK() OVER (
order by col1) - 1 - 2) / COUNT(*) OVER () < 60 / 100
LIMIT NULL OFFSET 2;

-- Using WITH TIES clause
select * from
TableFetch1
FETCH FIRST 2 ROWS ONLY;

select * from
TableFetch1
QUALIFY
(ROW_NUMBER() OVER (
ORDER BY
NULL) - 1) / COUNT(*) OVER () < 20 / 100;

select * from
TableFetch1
offset 2 rows FETCH NEXT 2 ROWS ONLY;

select * from
TableFetch1
QUALIFY
(ROW_NUMBER() OVER (
ORDER BY
NULL) - 1 - 2) / COUNT(*) OVER () < 60 / 100
LIMIT NULL OFFSET 2;

-- Using ORDER BY clause
select * from
TableFetch1
order by col1
FETCH FIRST 2 ROWS ONLY;

select * from
TableFetch1
QUALIFY
(ROW_NUMBER() OVER (
order by col1) - 1) / COUNT(*) OVER () < 20 / 100;

select * from
TableFetch1
order by col1 offset 2 rows FETCH FIRST 2 ROWS ONLY;

select * from
TableFetch1
QUALIFY
(ROW_NUMBER() OVER (
order by col1) - 1 - 2) / COUNT(*) OVER () < 60 / 100
LIMIT NULL OFFSET 2;

select * from
TableFetch1
FETCH FIRST 1 ROWS ONLY;

select * from
TableFetch1
LIMIT NULL OFFSET 2;

Nota

No Oracle, FETCH / OFFSET WITH TIES é ignorado quando nenhum ORDER BY é especificado em SELECT. Esse caso será transformado em um FETCH / OFFSET com a palavra-chave ONLY no Snowflake. Observe que no Snowflake a palavra-chave ONLY não tem efeito nos resultados e é usada apenas para facilitar a leitura.

Pivô¶

O Snowflake não é compatível com as seguintes instruções:\ - Rename columns \ - Multiple Columns

Oracle:¶

select * from schema1.table1
PIVOT(count(*) as count1 FOR (column1, column2) IN (row1 as rowName));

Snowflake:¶

select * from
schema1.table1
!!!RESOLVE EWI!!! /*** SSC-EWI-0015 - PIVOT/UNPIVOT RENAME COLUMN NOT SUPPORTED ***/!!!
PIVOT (count(*)
                !!!RESOLVE EWI!!! /*** SSC-EWI-0015 - PIVOT/UNPIVOT MULTIPLE COLUMN NOT SUPPORTED ***/!!!
                FOR (column1, column2)
!!!RESOLVE EWI!!! /*** SSC-EWI-0015 - PIVOT/UNPIVOT RENAME COLUMN NOT SUPPORTED ***/!!!
IN (row1 as rowName));

Unpivot¶

O Snowflake não é compatível com as seguintes instruções:\ - INCLUDE / EXCLUDE NULLS

Oracle:¶

select * from schema1.table1 
UNPIVOT INCLUDE NULLS (column1 FOR column2 IN (ANY, ANY)); 

Snowflake:¶

select * from
schema1.table1
!!!RESOLVE EWI!!! /*** SSC-EWI-0015 - PIVOT/UNPIVOT INCLUDE NULLS NOT SUPPORTED ***/!!!
UNPIVOT ( column1 FOR column2 IN (
ANY,
ANY));

Transformação de JOIN (+) para sintaxe ANSI¶

Perigo

Esta tradução está atualmente desativada e destina-se apenas a referência para traduções feitas com versões anteriores do SnowConvert AI. Para a tradução atual, verifique a seção acima.

O SnowConvert AI traduz a sintaxe de junção externa especial (+) NON-ANSI para a sintaxe de junção externa ANSI. Esta subseção mostra alguns exemplos:

Para LEFTOUTERJOIN¶

Exemplo 1:

Oracle:¶

-- Additional Params: --OuterJoinsToOnlyAnsiSyntax
SELECT d.department_name,
       e.employee_name      
FROM   departments d, employees e
WHERE  d.department_id = e.department_id (+) 
AND    d.department_id >= 30;

Snowflake:¶

SELECT d.department_name,
       e.employee_name
FROM
       departments d
       LEFT OUTER JOIN
              employees e
              ON d.department_id = e.department_id
WHERE
       d.department_id >= 30;

Exemplo 2:

Oracle:¶

-- Additional Params: --OuterJoinsToOnlyAnsiSyntax
SELECT d.department_name,
       e.employee_name      
FROM   departments d, employees e
WHERE  d.department_id(+)  = e.department_id 
AND    d.department_id >= 30;

Snowflake:¶

SELECT d.department_name,
       e.employee_name
FROM
       employees e
       LEFT OUTER JOIN
              departments d
              ON d.department_id = e.department_id
WHERE
       d.department_id >= 30;

Exemplo 3: Junção múltipla

Oracle:¶

-- Additional Params: --OuterJoinsToOnlyAnsiSyntax
SELECT d.department_name,
       e.employee_name      
FROM   departments d, employees e, projects p
WHERE  e.department_id(+) = d.department_id
AND    p.department_id(+) = d.department_id
AND    d.department_id >= 30;

Snowflake:¶

SELECT d.department_name,
       e.employee_name
FROM
       departments d
       LEFT OUTER JOIN
              employees e
              ON e.department_id = d.department_id
       LEFT OUTER JOIN
              projects p
              ON p.department_id = d.department_id
WHERE
       d.department_id >= 30;

Exemplo 4: Junção com outros tipos de condicionais

Oracle:¶

-- Additional Params: --OuterJoinsToOnlyAnsiSyntax
SELECT d.department_name,
       e.employee_name      
FROM   departments d, employees e
WHERE  d.department_id(+)  = e.department_id 
AND    d.location(+) IN ('CHICAGO', 'BOSTON', 'NEW YORK')
AND    d.department_id >= 30;

Snowflake:¶

SELECT d.department_name,
       e.employee_name
FROM
       employees e
       LEFT OUTER JOIN
              departments d
              ON d.department_id = e.department_id
              AND d.location IN ('CHICAGO', 'BOSTON', 'NEW YORK')
WHERE
       d.department_id >= 30;

Exemplo 5: Junção com (+) dentro de uma função

Oracle:¶

-- Additional Params: --OuterJoinsToOnlyAnsiSyntax
SELECT d.department_name,
       e.employee_name
FROM   departments d, employees e
WHERE SUBSTR(d.department_name, 1, NVL(e.department_id, 1) ) = e.employee_name(+);

Snowflake:¶

SELECT d.department_name,
       e.employee_name
FROM
       departments d
       LEFT OUTER JOIN
              employees e
              ON SUBSTR(d.department_name, 1, NVL(e.department_id, 1) ) = e.employee_name;

Aviso

Observe que alguns dos padrões que foram convertidos para LEFT OUTER JOIN podem recuperar as linhas em uma ordem diferente.

Para CROSSJOIN¶

Exemplo 6: Caso complexo que requer o uso de CROSS JOIN

Oracle:¶

SELECT d.department_name,
       e.employee_name,
       p.project_name,
       c.course_name 
FROM   departments d, employees e, projects p, courses c
WHERE
e.salary (+) >= 2000 AND
d.department_id = e.department_id (+)
AND p.department_id = e.department_id(+)
AND c.course_id  = e.department_id(+)
AND d.department_id >= 30;

Snowflake:¶

SELECT d.department_name,
       e.employee_name,
       p.project_name,
       c.course_name
FROM
       departments d
       CROSS JOIN projects p
       CROSS JOIN courses c
       LEFT OUTER JOIN
              employees e
              ON
              e.salary >= 2000
              AND
              d.department_id = e.department_id
              AND p.department_id = e.department_id
              AND c.course_id  = e.department_id
WHERE
       d.department_id >= 30;

Consultas hierárquicas¶

Hierarchical queries in Snowflake allow you to organize and retrieve data in a tree-like structure, typically using the CONNECT BY clause. This clause joins a table to itself to process hierarchical data in the table.

Amostra de padrões da origem¶

Oracle:¶

SELECT employee_ID, manager_ID, title
FROM employees
START WITH manager_ID = 1
CONNECT BY manager_ID = PRIOR employee_id;

Snowflake:¶

SELECT employee_ID, manager_ID, title
FROM
employees
START WITH manager_ID = 1
CONNECT BY
manager_ID = PRIOR employee_id;

Consulta Select Flashback¶

Descrição¶

Oracle

A cláusula de Flashback Query no Oracle recupera dados anteriores de uma tabela, visualização ou exibição materializada. No Oracle, os usos podem incluir:

Restaurar dados excluídos ou desfazer um commit incorreto, comparar os dados atuais com os dados correspondentes em um momento anterior, verificar o estado dos dados transacionais em um determinado momento e gerar ferramentas de geração de relatórios para dados passados, entre outros. (Documentação de consulta Flashback Query do Oracle).

Snowflake

O mecanismo equivalente no Snowflake para consultar dados do passado é a consulta AT | BEGIN. Observe que o único equivalente é para as instruções AS OF.

Além disso, o Snowflake tem uma documentação completa de «Time Travel» que permite consultar dados para clonar objetos, como tabelas, exibições e esquemas. Há limitações quanto aos dias de acesso aos dados passados ou excluídos (90 dias antes de passar para o status Fail-safe). Para obter mais informações, consulte a Documentação de Time Travel do Snowflake.

Sintaxe do Oracle

{ VERSIONS BETWEEN
  { SCN | TIMESTAMP }
  { expr | MINVALUE } AND { expr | MAXVALUE }
| AS OF { SCN | TIMESTAMP } expr
}

Sintaxe do Snowflake

SELECT ...
FROM ...
  {
   AT( { TIMESTAMP => <timestamp> | OFFSET => <time_difference> | STATEMENT => <id> | STREAM => '<name>' } ) |
   BEFORE( STATEMENT => <id> )
  }
[ ... ]

Nota

Observe que a ID da consulta deve fazer referência a uma consulta executada dentro de 14 dias. Se a ID fizer referência a uma consulta com mais de 14 dias, o seguinte erro será retornado: Erro: statement <query_id> not found. Para contornar essa limitação, use o registro de data e hora da consulta referenciada. (Snowflake AT | Antes da documentação)

Amostra de padrões da origem¶

Os dados a seguir são usados nos exemplos a seguir para gerar os resultados da consulta.

Oracle¶

CREATE TABLE Employee (
    EmployeeID NUMBER PRIMARY KEY,
    FirstName VARCHAR2(50),
    LastName VARCHAR2(50),
    EmailAddress VARCHAR2(100),
    HireDate DATE,
    SalaryAmount NUMBER(10, 2)
);

INSERT INTO Employee VALUES (1, 'Bob', 'SampleNameA', 'sample@example.com', TO_DATE('2023-01-15', 'YYYY-MM-DD'), 11111.00);
INSERT INTO Employee VALUES (2, 'Bob', 'SampleNameB', 'sample@example.com', TO_DATE('2023-01-15', 'YYYY-MM-DD'), 11111.00);
INSERT INTO Employee VALUES (3, 'Bob', 'SampleNameC', 'sample@example.com', TO_DATE('2022-03-10', 'YYYY-MM-DD'), 11111.00);
INSERT INTO Employee VALUES (4, 'Bob', 'SampleNameD', 'sample@example.com', TO_DATE('2022-03-10', 'YYYY-MM-DD'), 11111.00);
INSERT INTO Employee VALUES (5, 'Bob', 'SampleNameE', 'sample@example.com', TO_DATE('2022-03-10', 'YYYY-MM-DD'), 11111.00);

Snowflake¶

CREATE OR REPLACE TABLE Employee (
       EmployeeID NUMBER(38, 18) /*** SSC-FDM-0006 - NUMBER TYPE COLUMN MAY NOT BEHAVE SIMILARLY IN SNOWFLAKE. ***/ PRIMARY KEY,
       FirstName VARCHAR(50),
       LastName VARCHAR(50),
       EmailAddress VARCHAR(100),
       HireDate TIMESTAMP /*** SSC-FDM-OR0042 - DATE TYPE COLUMN HAS A DIFFERENT BEHAVIOR IN SNOWFLAKE. ***/,
       SalaryAmount NUMBER(10, 2) /*** SSC-FDM-0006 - NUMBER TYPE COLUMN MAY NOT BEHAVE SIMILARLY IN SNOWFLAKE. ***/
   )
   COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"oracle"}}'
   ;

   INSERT INTO Employee
   VALUES (1, 'Bob', 'SampleNameA', 'sample@example.com', TO_DATE('2023-01-15', 'YYYY-MM-DD'), 11111.00);

   INSERT INTO Employee
   VALUES (2, 'Bob', 'SampleNameB', 'sample@example.com', TO_DATE('2023-01-15', 'YYYY-MM-DD'), 11111.00);

   INSERT INTO Employee
   VALUES (3, 'Bob', 'SampleNameC', 'sample@example.com', TO_DATE('2022-03-10', 'YYYY-MM-DD'), 11111.00);

   INSERT INTO Employee
   VALUES (4, 'Bob', 'SampleNameD', 'sample@example.com', TO_DATE('2022-03-10', 'YYYY-MM-DD'), 11111.00);

   INSERT INTO Employee
   VALUES (5, 'Bob', 'SampleNameE', 'sample@example.com', TO_DATE('2022-03-10', 'YYYY-MM-DD'), 11111.00);

1. AS OF with TIMESTAMP case¶

Oracle¶

SELECT * FROM employees
AS OF TIMESTAMP
TO_TIMESTAMP('2023-09-27 07:00:00', 'YYYY-MM-DD HH:MI:SS')
WHERE last_name = 'SampleName';

Snowflake¶

SELECT * FROM
employees
!!!RESOLVE EWI!!! /*** SSC-EWI-OR0135 - DATA RETENTION PERIOD MAY PRODUCE NO RESULTS ***/!!!
AT (TIMESTAMP =>
TO_TIMESTAMP('2023-09-27 07:00:00', 'YYYY-MM-DD HH:MI:SS'))
WHERE last_name = 'SampleName';

2. AS OF with SCN case¶

Oracle¶

SELECT * FROM employees
AS OF SCN
TO_TIMESTAMP('2023-09-27 07:00:00', 'YYYY-MM-DD HH:MI:SS')
WHERE last_name = 'SampleName';

Snowflake¶

SELECT * FROM
employees
!!!RESOLVE EWI!!! /*** SSC-EWI-0040 - THE 'FLASHBACK QUERY' CLAUSE IS NOT SUPPORTED IN SNOWFLAKE ***/!!!
AS OF SCN
TO_TIMESTAMP('2023-09-27 07:00:00', 'YYYY-MM-DD HH:MI:SS')
WHERE last_name = 'SampleName';

Problemas conhecidos¶

A opção quando está usando SCN não é suportada.
A instrução VERSION não é compatível com o Snowflake.

EWIs relacionados¶

SSC-EWI-0040: Instrução incompatível.
SSC-EWI-OR0135: Atual da cláusula não é suportada no Snowflake.
SSC-FDM-0006: A coluna do tipo número pode não se comportar de forma semelhante no Snowflake.
SSC-FDM-OR0042: O tipo de data transformado em carimbo de data/hora tem um comportamento diferente.