Yes, id_other_table IS a foreign key to id and usually I've got records in each table.
Thanks to all of you! Il ven, 2004-01-23 alle 21:45, [EMAIL PROTECTED] ha scritto: > As for the outer join, I think that the problem was ambiguous. > > Is id_other_table a foreign key to id? Is there at most one row in each > table? > > > On Fri, Jan 23, 2004 at 05:15:56PM -0300, Martín Marqués wrote: > >> Mensaje citado por Marco Lazzeri <[EMAIL PROTECTED]>: > >> > >> > I want to write a query on table 'main' that if 'id_other_table' is > >> null > >> > returns value from itself, from table 'other' otherwise. > >> > >> SELECT CASE WHEN id_other_table IS NULL THEN id_other_table > >> ELSE id > >> FROM main,other > > > > What about COALESCE? > > > > SELECT COALESCE(id_other_table, id) FROM main, other WHERE ... > > > > (Also probably an OUTER JOIN is needed -- see > > http://www.varlena.com/GeneralBits/56.php) ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
