I'm trying to find/delete all records in table A that are no longer referenced by tables B or C. There are about 4 million records in table A, and several hundred million in tables B and C. Is there something more efficient than: select address_key, address from addresses where ( not exists(select 1 from B where BField=addresses.address_key limit 1) ) and ( not exists(select 1 from C where CField=addresses.address_key limit 1) ) Of course, all fields above are indexed. There are foreign key references in B and C to A. Is there some way to safely leverage that? Wes
