GilaMonster (2/10/2011)
deepak.a (2/10/2011)
Thanks for reply,if we use columns or * will it make any performance difference? and alsoLike ex : if exists(Select 1 ... ) or if exists(select Top 1 1 ....)
No and no
using a SELECT 1, avoids having to look at any of the meta-data that is not even needed to check the existancee of the records form the table?
Got nothing to do with metadata. EXISTS only cares about whether there is a row or not, it doesn't look at columns, it doesn't care.
Don't waste your time trying to do micro-optimisations. Silly tricks like this do not make major performance differences.
Thanks a lot Gail Shaw for your reply