Re: select distinct and order by

I don't know if this will work, but why not try it ? :)

select distinct fullname, distinct staff_id, loginname from staff
where staff_id in
(select staff_id from staffmembership where staffgroup_id=#SomeIdValue#)
order by fullname, staff_id

Next one is more complicate but with more chances to succeed :)

select staff_id, fullname, loginname from (
select distinct on (staff_id) staff_id, fullname, loginname from staff
where staff_id in
(select staff_id from staffmembership where staffgroup_id=#SomeIdValue#)
order by staff_id
)
order by fullname

Let me know
:)
----- Original Message -----
From: Stijn Vanroye
To: pgsql-sql(at)postgresql(dot)org
Sent: Wednesday, April 28, 2004 12:27
Subject: [SQL] select distinct and order by

Hello everybody,

I have a short question:

I'm trying to run the following query:
select distinct on (staff_id) staff_id, fullname, loginname from staff
where staff_id in
(select staff_id from staffmembership where staffgroup_id=#SomeIdValue#)
order by fullname

I get the follwing error:
select distinct on expressions must match the initial order by expression

Does this mean that I can only order by the same fields as the ones that I use in the distinct?
If so, is there still a way that I can select distinct on the keyfield, and still sort by the name. However unlikely, it could happen that two people have the same name, so a distinct on fullname could make problems.

The facts:
- PostgreSQL 7.3.2 running on RH 9
- pgODBC 7.3.0200
- Borland Delphi 7 enterprise

Regards,

Stijn Vanroye

-=[Today I got more responsabilities from my boss, as from now I'm responsible for everything that goes wrong ...]=-

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