Can UNION ALL be faster than JOINs or do my JOINs just suck?

Question

I have a Notes table with a uniqueidentifier column that I use as a FK for a variety of other tables in the database (don\'t worry, the uniqu

Answer 1

The UNION ALL version would probably be satisfied quite easily by 2 index seeks. OR can lead to scans. What do the execution plans look like?

Also have you tried this to avoid accessing Notes twice?

;WITH J AS
(
SELECT UniqueID FROM Leads WHERE LeadID = @LeadID
UNION ALL
SELECT UniqueID FROM Quotes WHERE LeadID = @LeadID
)

SELECT N.*  /*Don't use * though!*/
FROM Notes N  
JOIN J ON N.TargetUniqueID = J.UniqueID