Re: [HACKERS] Parser bug?

Bruce Momjian wrote:
... >>   >> bray=> select rcname, rcsrc from pg_relcheck where rcrelid = >>   >> '115404'::oid and rcrelid in (select
min(rcrelid)from pg_relcheck >>   >> group by rcname); ERROR:  parser: Subselect has too many or too >>   >> few
fields.>>   >>  >>   >> The subselect only produces one column; so I think that the >>   >> error message is wrong. >>
> >>   >What is the GROUP BY doing?
 
...
 >Maybe I should be clearer.  You are grouping by a column that is not in >the target list.  If you try the subquery on
itsown, it should fail >with a better error message.
 
It doesn't fail; it produces the results I want.
 bray=> select min(rcrelid) from pg_relcheck group by rcname;    min ------ 115940 115026 115026 115026 ... etc ...

Any way, why should it be an error to group by a column that is not in the
results list, if the results list comprises aggregates only?

(Mind you, I think I have not yet got a reliable way of finding the
ultimate ancestor of an inherited constraint.  Is it actually possible to
do this with queries or do we have to add a boolean flag to pg_relcheck
to be set where the constraint is/is not inherited?)

-- 
Oliver Elphick                                Oliver.Elphick@lfix.co.uk
Isle of Wight                              http://www.lfix.co.uk/oliver              PGP key from public servers; key
ID32B8FAA1                ========================================    "Jesus saith unto him, I am the way, the truth,
andthe     life; no man cometh unto the Father, but by me."                                              John 14:6