On Tue, 2007-04-17 at 10:15 +0100, Richard Huxton wrote: > garry saddington wrote: > > On Tue, 2007-04-17 at 09:21 +0100, Richard Huxton wrote: > >> garry saddington wrote: > >>> I am trying this syntax which is my interpretation of the docs: > >>> > >>> delete from siblings s1 using siblings s2 > >>> WHERE s1.principal = s2.principal > >>> and s1.sibling=175 > >>> > >>> Can anyone tell me where I am going wrong? > >> 1. What's happening - are you getting an error? > > I am getting a syntax error (via psycopg) at or near s1 - perhaps this is a psycopg problem? > >> 2. What is the query supposed to do? I can't see why you're not just doing: > >> DELETE FROM siblings WHERE sibling=175; > >> > > > > I am keeping a record of siblings in a school. The user chooses one > > student and there siblings such that id's are entered into a table as > > such: > > TABLE SIBLINGS: > > > > principal sibling > > 809 234 > > 809 785 > > 809 345 > > 809 809 > > > What I am trying to do is to allow the user to correct input mistakes by > > deleting all the siblings of one family at the same time by choosing > > just one of the siblings. I hope this clears things up. > > Ah, OK. The error then is that you're testing against s1.sibling not > s2.sibling. "delete from siblings s1 ... and s1.sibling=175" which means > you're not using s2 at all. > > You might find it clearer with a subquery: > DELETE FROM siblings WHERE principal = ( > SELECT principal FROM siblings WHERE sibling=234 > ); Thanks, can't think why I went the complicated route! Regards Garry
