'GROUP BY' / 'DISTINCT' interaction bug?

Started by Mark Hollomonover 25 years ago2 messages
#1Mark Hollomon
mhh@nortelnetworks.com

Is this a known problem? Is there a work-around?

create table t (c char, i int);
insert into t values ('a', 1);
insert into t values ('a', 1);
insert into t values ('a', 2);
insert into t values ('b', 2);

select distinct on (c, i) c, count(i) from t group by c;
ERROR: Attribute t.i must be GROUPed or used in an aggregate function

--

Mark Hollomon
mhh@nortelnetworks.com
ESN 451-9008 (302)454-9008

#2Tom Lane
tgl@sss.pgh.pa.us
In reply to: Mark Hollomon (#1)
Re: 'GROUP BY' / 'DISTINCT' interaction bug?

"Mark Hollomon" <mhh@nortelnetworks.com> writes:

select distinct on (c, i) c, count(i) from t group by c;
ERROR: Attribute t.i must be GROUPed or used in an aggregate function

Why do you think that's a bug? The DISTINCT clause requires use of
the ungrouped value of i, doesn't it?

regards, tom lane