Home Forums SQL Server 2008 T-SQL (SS2K8) CASE Statement in SELECT clause to convert into the where clause RE: CASE Statement in SELECT clause to convert into the where clause

  • worker bee (11/14/2012)


    Okay, I have a CASE stmt that is in the SELECT clause. I basically want to get rid of the CASE stmt and place the information in the where clause. I have done this but I get two of everything in my results. Please help!

    --OLD

    SELECT DISTINCT

    CASE a.COL1

    WHEN '26' THEN b.COLB

    END AS OUTPUT1,

    CASE a.COL1

    WHEN '27' THEN b.COL2

    END AS OUTPUT2

    FROM

    TBL1 a, TBL2 b

    WHERE

    a.COL1 = b.COL1 and

    a.COL2 = b.COL2 and

    a.COL1 > 1

    --NEW

    SELECT DISTINCT

    b.COL2 AS OUTPUT1

    b.COL2 AS OUTPUT2

    FROM

    TBL1 a, TBL2 b

    a.COL1 = b.COL1 and

    a.COL2 = b.COL2 and

    a.COL1 > 1 AND

    b.COL2 IN ('26', '27')

    Remember that we can't see your screen from here and we don't know what your tables or data look like. That being said those two queries are not doing anywhere near the same thing. Why do you think you need to move this to the where clause?

    I would recommend you use the newer ANSI style of join instead of the old style. They will produce the same result but is less error prone and more legible. Your first query would become something like this:

    SELECT DISTINCT

    CASE a.COL1 WHEN '26' THEN b.COLB END AS OUTPUT1

    ,CASE a.COL1 WHEN '27' THEN b.COL2 END AS OUTPUT2

    FROM TBL1 a

    inner join TBL2 b on a.COL1 = b.COL1 AND a.COL2 = b.COL2

    where a.COL1 > 1

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