Question

Ok, so I’m trying to select an amount of rows from a column that holds the value 3, but only if there are no rows containing 10 or 4, if there are rows containing 10 or 4 I only want to show those.

What would be a good syntax to do that? So far I’ve been attempting a CASE WHEN statement, but I can’t seem to figure it out.

Any help would be greatly appreciated.

(My database is in an MS SQL 2008 server)

Answer 1

Depending on the size of your table and its indexes, it may be more efficient to calculate which values you want before the query

declare @UseThree as bit = 1;
if exists (select 1 from testtable where rowval in (10,4))
set @UseThree = 0;

select COUNT(*) 
from testtable
where (@UseThree = 1 AND rowval=3)
    OR
    (@UseThree = 0 AND rowval in (10,4))