Hi,

Can any one please tell me the difference between not exists and except clauses in the sql's?

Thanks,

EXCEPT compares all (paired)columns of two full-selects.
NOT EXISTS compares two or more tables accoding to the conditions specified in WHERE clause in the sub-query following NOT EXISTS keyword.

EXCEPT can be rewritten by using NOT EXISTS.
(EXCEPT ALL can be rewritten by using ROW_NUMBER and NOT EXISTS.)