On Mon, Jun 30, 2008 at 11:16:54AM -0500, Stephen Woodbridge wrote: > Hi all, > > I could use a little help with a join: > > select a.tlid, b.fullname, b.paflag, a.mtfcc, c.fromhn, c.tohn, c.side, > c.zip, c.plus4, a.statefp, a.countyfp > from featnames b, addr c, addrfn d, edges a > where a.tlid=b.tlid and b.tlid=c.tlid and b.linearid=d.linearid and > c.arid=d.arid and a.roadflg='Y' > order by a.tlid, b.fullname, c.side ; > > I need to get back records for every record in edges even if there is no > matching tlid in the addr table. > > How do I do that?
The SELECT foo FROM a,b,c,d WHERE a.id = b.id AND b.id=c.id is called inner join. Just have a look at the Postgresql manual Joins are described in depth at the beginning you want a LEFT or RIGHT JOIN here, such as SELECT a.id, b.id FROM tablea as a LEFT JOIN tableb as b ON (a.id =b.id) This includes all from a and fills missing rows from b with nulls Marc _______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
