Question

Can i reuse a complex select Where clause to different group by?

What i am doing:

(Select X, Count(*) From [Big where clause with many tables] Group By X)
Union All
(Select Y, Count(*) From [Big where clause with many tables] Group By Y)

How can i optmise this?

I’m using SQL Server 2008 and this will go inside a Function, but could be a stored procedure.

Answer 1

WITH basequery AS (Select * From [Big where clause with many tables])
SELECT X, COUNT(*) FROM basequery GROUP BY X
UNION ALL
SELECT Y, COUNT(*) FROM basequery GROUP BY Y;

CTEs were made for situations like this.