Question

If I have a subquery which does the following;

Select
    Min(S_Date)
,   Col1
,   Col2
From 
(
    Select Dateadd(whatever) as S_Date, Userid 
    from tbl1 as t 
    where S_Date >'today'
)

How can I add another clause so that value from Col1 is only selected if another condition is met, i.e col3 = ‘doit’. I guess I am trouble understanding how to use two where clauses in different places in a subquery.

Answer 1

You need to use a CASE statement:

SELECT 
    s_date
    ,CASE Col3 WHEN 'doit' THEN Col1 ELSE Col2 END AS selection
FROM (
    SELECT 
       Sdate
       , Col1
       , Col2
       , Col3
    FROM foo
    WHERE s_Date > GETDATE()
 ) AS sub