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, vhikida@inreach.com 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 <marcomail@noze.it>:
> >>
> >> > 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)
