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(at)candle(dot)pha(dot)pa(dot)us