GermanDBA (2/12/2008)
So the performance winner with select 1 is that the server doesn't take the hit for column checks.
That's what I understood from Conor's post. It's probably a very, very minimal hit. Just bear in mind that this is only for Exists subqueries.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability