Hash join are usually better when the cardinality to process is high. With small cardinality nested loop tend to be more efficient. The cardinality here for both SQL are not that big. check what oracle says about it : http://download-uk.oracle.com/docs/cd/B19306_01/server.102/b14211/sql_1016.htm#sthref1085 http://download-uk.oracle.com/docs/cd/B19306_01/server.102/b14211/optimops.htm#sthref1397 B.Polarski http://www.smenu.org
