CASE

Translation reference for CASE statements

Description

The CASE statement chooses from a sequence of conditions and runs a corresponding statement. For more information regarding Oracle CASE, check here.

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

Simple case

[ <<label>> ] CASE case_operand
  WHEN boolean_expression THEN statement ;
  [ WHEN boolean_expression THEN statement ; ]...
  [ ELSE statement [ statement ]... ;
END CASE [ label ] ;

CASE ( <expression_to_match> )
    WHEN <expression> THEN
        <statement>;
        [ <statement>; ... ]
    [ WHEN ... ]
    [ ELSE
        <statement>;
        [ <statement>; ... ]
    ]
END [ CASE ] ;

Searched case

[ <<label>> ] CASE
  WHEN boolean_expression THEN statement ;
  [ WHEN boolean_expression THEN statement ; ]...
  [ ELSE statement [ statement ]... ;
END CASE [ label ];

CASE
    WHEN <boolean_expression> THEN
        <statement>;
        [ <statement>; ... ]
    [ WHEN ... ]
    [ ELSE
        <statement>;
        [ <statement>; ... ]
    ]
END [ CASE ] ;

Sample Source Patterns

Sample auxiliar table

IN -> Oracle_01.sql

CREATE TABLE case_table(col varchar(30));

OUT -> Oracle_01.sql

CREATE OR REPLACE TABLE case_table (col varchar(30))
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
;

Simple Case

Oracle

IN -> Oracle_02.sql

CREATE OR REPLACE PROCEDURE caseExample1 ( grade NUMBER )
IS
RESULT VARCHAR(20);
BEGIN
   <<CASE1>>
   CASE grade
    WHEN 10 THEN RESULT:='Excellent';
    WHEN 9 THEN RESULT:='Very Good';
    WHEN 8 THEN RESULT:='Good';
    WHEN 7 THEN RESULT:='Fair';
    WHEN 6 THEN RESULT:='Poor';
    ELSE RESULT:='No such grade';
  END CASE CASE1;
  INSERT INTO CASE_TABLE(COL) VALUES (RESULT);
END;

CALL caseExample1(6);

CALL caseExample1(4);

CALL caseExample1(10);

SELECT * FROM CASE_TABLE;

|COL          |
|-------------|
|Poor         |
|No such grade|
|Excellent    |

Snowflake Scripting

OUT -> Oracle_02.sql

CREATE OR REPLACE PROCEDURE caseExample1 (grade NUMBER(38, 18))
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
EXECUTE AS CALLER
AS
$$
  DECLARE
    RESULT VARCHAR(20);
  BEGIN
    !!!RESOLVE EWI!!! /*** SSC-EWI-0094 - LABEL DECLARATION FOR A STATEMENT IS NOT SUPPORTED BY SNOWFLAKE SCRIPTING <<CASE1>> ***/!!!
    CASE :grade
      WHEN 10 THEN
        RESULT := 'Excellent';
      WHEN 9 THEN
        RESULT := 'Very Good';
      WHEN 8 THEN
        RESULT := 'Good';