Question

I’m trying to change my WHERE clause based on the value of one column of my table.
My tables are:

server_updates

k1ID        updID
----------- -----------

server_updates_cat

sucID        updID       catID       selectChildren   includeNullType
-----------  ----------- ----------- ---------------- --------------

server_updates_types

sucID       typeID
----------- -----------

And here’s what I’m doing:

DECLARE @k1_catID INT
DECLARE @k4_type INT

SET @k1_catID = 30
SET @k4_type = 1

SELECT suc.sucID, suc.updID FROM server_updates su
INNER JOIN server_updates_cat suc ON suc.updID = su.updID

WHERE
includeNullType = 0
    AND suc.catID = @k1_catID
    AND selectChildren = 1
    AND @k4_type IN (SELECT typeID FROM server_updates_types sut WHERE sut.sucID = suc.sucID)
OR
includeNullType = 1 
    AND KSUC.catID = @k1_catID
    AND selectChildren = 1
    AND (@k4_type IN (SELECT typeID FROM server_updates_types sut WHERE sut.sucID = suc.sucID) OR @k4_type IS NULL)

I would like to not have to repeat all conditions either includeNullType = 0 or includeNullType = 1, but change the only thing I really need to change, which is:

@k4_type IN (SELECT typeID FROM server_updates_types sut WHERE sut.sucID = suc.sucID)

Is there another way of doing that?

Answer 1

WHERE suc.catID = @k1_catID
AND selectChildren = 1
AND (
(includeNullType = 0   
AND @k4_type IN (SELECT typeID FROM server_updates_types sut WHERE sut.sucID = suc.sucID))
OR
(includeNullType = 1 
    AND (@k4_type IN (SELECT typeID FROM server_updates_types sut WHERE sut.sucID = suc.sucID) OR @k4_type IS NULL))
)