The minus technique is the best I think to compare tables, but I think attractive the idea of the hash column. ( if you store through a trigger or a night process a hash value column per row ) Because 1) you could create an index on the hash column, which is several times smalles than a all columns index. 2) you can do other queries, for example to see if this record is duplicated, etc. etc. This allows you to easity to do another administrative operations. So Is a good idea anyway. -- //www.freelists.org/webpage/oracle-l