Performance of SQL Server 2005 Query

Question

-------------------- this takes 4 secs to execute (with 2000 000 rows) WHY?---------------------

DECLARE @AccountId INT 
DECLARE @Max INT 
DECLARE @MailingLi         


        

Answer 1

Add OPTION (RECOMPILE) to the end of the query.

SQL Server doesn't "sniff" the values of the variables so you will be getting a plan based on guessed statistics rather than one tailored for the actual variable values.