OK, this does not work:
select max(t1.When), t1.Pt_Id, t2.DateOfBirth
from PtStaffAccess t1, Person t2
where t1.Pt_Id = t2.id
group by t1.Pt_Id;
But this does:
select max(t1.When), t1.Pt_Id, min(t2.DateOfBirth)
from PtStaffAccess t1, Person t2
where t1.Pt_Id = t2.id
group by t1.Pt_Id;
Now the
On 28 January 2010 21:32, Scott Ribe scott_r...@killerbytes.com wrote:
OK, this does not work:
select max(t1.When), t1.Pt_Id, t2.DateOfBirth
from PtStaffAccess t1, Person t2
where t1.Pt_Id = t2.id
group by t1.Pt_Id;
But this does:
select max(t1.When), t1.Pt_Id, min(t2.DateOfBirth)
from
You can't include an aggregate in the select if you don't group by
non-aggregates, so it should be:
select max(t1.When), t1.Pt_Id, t2.DateOfBirth
from PtStaffAccess t1, Person t2
where t1.Pt_Id = t2.id
group by t1.Pt_Id, t2.DateOfBirth;
I was aware that I could alternatively group by all
-Original Message-
From: pgsql-general-ow...@postgresql.org [mailto:pgsql-general-
ow...@postgresql.org] On Behalf Of Scott Ribe
Sent: Thursday, January 28, 2010 2:10 PM
To: Thom Brown
Cc: pgsql-general
Subject: Re: [GENERAL] SQL question re aggregates joins
You can't include
Scott Ribe scott_r...@killerbytes.com writes:
Given that t2.id is the primary key, grouping by any other column of t2 is
really redundant. I know *what* SQL won't allow me to do, I'm interested in
knowing if there's some reason *why* other than historical...
SQL92 says so. More recent
