Re: join queries

"David M. Kaplan" wrote:
  >Hi,
  >
  >I have a query which seems like it should easy, but isnt.  I have two
  >tables, a and b that look like this:
  >
  >a)
  >
  > id | c1
  >--+--
  >  1 | a
  >  2 | b
  >  3 | c
  >
  >b)
  >
  > id | c2
  >--+--
  >  2 | b
  >
  >and I would like to do a query which returns
  >
  > id | c1 | c2
  >--+--+--
  >  1 | a  |
  >  2 | b  | b
  >  3 | c  |
  >
  >The simplest thing I could find was
  >
  >SELECT a.*, (SELECT b.c2 WHERE a.id=b.id) AS c2;
  >
  >This works, but is extremely slow for more complex examples.  Is there a
  >better way to do this in postgresql??  I think MS Access has inner and
  >outer joins to solve this problem.  Is there a postgresql equivalent?

SELECT a.id, c1, c2 FROM a LEFT OUTER JOIN b ON a.id = b.id

This requires PostgreSQL 7.1


--
Oliver Elphick                                Oliver.Elphick@lfix.co.uk
Isle of Wight                              http://www.lfix.co.uk/oliver
PGP: 1024R/32B8FAA1: 97 EA 1D 47 72 3F 28 47  6B 7E 39 CC 56 E4 C1 47
GPG: 1024D/3E1D0C1C: CA12 09E0 E8D5 8870 5839  932A 614D 4C34 3E1D 0C1C
                 ========================================
     "But as many as received him, to them gave he power to
      become the sons of God, even to them that believe on
      his name."    John 1:12