Re: SQL question ...

In article <52ssot$j7m@cssun.mathcs.emory.edu>, Scott Rubin <scottr@fourgen.com> writes >Here is a way that should work for engines with pre-fragmented tables: > > >select A.rowid as row_id > from A, B > where A.C1 = B.C1 > and A.C2 = B.C2 > and XXX > into temp t1 with no log;> >delete from A > where rowid in (select row_id from t1);> >------------------------------------------------------------------------------- > >At 07:15 PM 10/1/96 GMT, you wrote: >>Assume I have table A with composite key C1, C2 and >> table B with composite key C1, C2 . >> >> >>How do I delete from A where C1,C2 in(select C1,C2 from B where XXX) ; >> >>Assume C1,C2 may not be chars so no || deals ... >>also, no cascading deletes ... Here is a way which will work under all versions but I'm not sure why it works....(I got this from an Ingres expert and used to today). This was joining on 4 columns deleting 26 rows out of ~1300. It does work but why?? Just when I though I knew SQL.... delete from A where 1 in (select 1 from A,B where A.C1 = B.C1 and A.C2 = B.C2) -- David Williams