You can implement this with Dynamic SQL as well
DECLARE@TableName VARCHAR(100), @SQL VARCHAR(1000)
SET@TableName = 'agent'
SET@SQL= ' SELECT* '
+ ' FROM ' + @TableName
+ ' WHERE ' + CASE WHEN @TableName IN ( 'product', 'customer' ) THEN 'statecode = 0' ELSE '1=1' END
EXECUTE ( @SQL )
How to post data/code on a forum to get the best help - Jeff Moden
http://www.sqlservercentral.com/articles/Best+Practices/61537/