Re: SQL Help?

Hi Barry-- First, I want to see if I understand what you mean, then I'll take a shot at some SQL to solve the problem. I take it you have two tables, "a" and "b". They may look something like this: Table: a ------------ id name --- ------ 001 Bob 002 Ted 003 Mary 004 Sandy Table: b ------------ id --- 002 003 And you want your result table to look something like: id name selected --- ------ -------- 001 Bob 0 002 Ted 1 003 Mary 1 004 Sandy 0 What you're trying to do is not very set-oriented (SQL is very set-oriented), so how about gathering the two sets you're talking about and returning the union of the two? Something like: select a.id as id, name, 1 as selected from a, b where a.id = b.id union select a.id as id, name, 0 as selected from a where a.id NOT IN (select id from b); There are undoubtedly other ways to do this, but the above query works on an old PostgreSQL installation I mess around with sometimes. Hope this helps. Doug At 02:30 PM 8/16/01 -0700, Barry Prentiss wrote: >Hi, > Here's another SQL query problem: > >How do I construct a query that returns 1 if a value is present and zero if >it is not, for a list of values returned in another query? > >i.e. select a.id, a.name, c.selected from table-with-id-and-name a, > (select 1 as selected from another-table b if a.id = b.id > or select 0 as selected from another-table b if a.id != b.id ) c; > > Thx in Advance, > Barry Prentiss