Re: [HACKERS] subquery syntax broken

> I believe it has to do with the fact that '=' has right precedence.
> Thomas, can you comment.  Maybe we need to %right 'Op' at that point so
> it doesn't shift too early?

No, the single-character operators each need their own code in the parser.
Check near line 2980 in the parser for examples from the "a_expr" syntax. You
just need to replicate the subselect "Op" definition blocks and substitute
each of '=', '<', and '>' in the copies. The existing "Op" code handles the
multi-character operators such as '<=' and '>='...

                                              - Tom

> > It doesn't work for =, >, etc:
> >
> > vac=> select * from x where y = (select max(y) from x);
> > ERROR:  parser: parse error at or near "select"
> >
> > but work for others:
> >
> > vac=> select * from x where y @ (select max(y) from x);
> > ERROR:  There is no operator '@' for types 'int4' and 'int4'
> >         You will either have to retype this query using an explicit cast,
> >         or you will have to define the operator using CREATE OPERATOR
> >
> > Also:
> >
> > > +               | a_expr Op '(' SubSelect ')'
> > > +                               {
> > > +                                       SubLink *n = makeNode(SubLink);
> > > +                                       n->lefthand = lcons($1, NULL);
> > > +                                       n->oper = lcons($2,NIL);
> > > +                                       n->useor = false;
> > > +                                       n->subLinkType = ALL_SUBLINK;
> >                                                            ^^^^^^^^^^^
> >                    should be EXPR_SUBLINK
> > > +                                       n->subselect = $4;
> > > +                                       $$ = (Node *)n;
> > > +                               }
> >
> > Vadim
> >
>
> --
> Bruce Momjian
> maillist@candle.pha.pa.us