SQL CASE and local variables

问题:

I would like to know how I can use local variables in CASE statements in SQL?

This script gives me an error:

    DECLARE @Test int;
    DECLARE @Result char(10);
    SET @Test = 10;

    CASE @Test
    WHEN @Test = 10
    THEN SET @Result='OK test'
    END
    Print @Result;

I use MS SQL 2008.

回答1:

Two ways to use CASE in this scenario with MSSQL

DECLARE 
    @test   int,
    @result char(10)

SET @test = 10

SET @result = CASE @test
    WHEN 10 THEN 
        'OK test'
    ELSE
        'Test is not OK'
END

PRINT @result;

SET @result = CASE 
    WHEN @test = 10 THEN 
        'OK test'
    ELSE
        'Test is not OK'
END

PRINT @result

回答2:

try this:

DECLARE @Test int;
DECLARE @Result char(10);
SET @Test = 10;

select @Result=
CASE @Test
WHEN 10 THEN  'OK test'
END

Print @Result;

回答3:

In SQL Server I would write it like this:

DECLARE @Test int;
DECLARE @Result char(10);
SET @Test = 10;

SET @Result = CASE @Test
WHEN 10
 THEN 'OK test'
END
Print @Result;

The WHEN clause does not have @Test = 10, as the @Test variable is stated in the CASE clause.

See the CASE documentation for SQL Server.

回答4:

CASE @Test WHEN 10 THEN

回答5:

DECLARE @Test int;
SET @Test = 10;

SELECT 
CASE @Test
WHEN 10
THEN 'OK test'
END

For SQL server 2005