Re: delete based on multipart key

In article <33421BB9.2197@gte.net>, Douglas Wilson <dgwilson@gte.net> writes >Rudy Fernandes wrote: >> >> In article <pz67yez52w.fsf@eeyore.ibcinc.com>, > I can't figure out an efficient way >> >to delete all the rows whose keys appear in a second table. > >Which reminds me, I've mentioned this before and I'll mention it >again, there ought to be syntax for this multi-part sort of thing like >so: > >delete from first_table >where a,b in (select a,b from second_table)> There is :- delete from first_table where 1 in (select 1 from first_table,second_table where first_table.a = second_table.a and first_table.b = second_table.b) No - I don't fully undetstand it either although I can see how it could work (subselect 'marks' the rows and delete deletes rows in the 'marked' set) and it does!!! Somehow though I still don't feel I totally understand WHY it works... >Enough griping, back to work, >Douglas Wilson > -- David Williams