Re: sub-sel/group problem

On Monday 11 August 2003 11:24 am, Gary Stainburn wrote:
> Hi folks,
>
> I don;t know if it's cos it's Monday or what, but I can't see what's wrong
> here.
>
> I've got two tables, turns which holds a turn number, a task, and where
> appropriate a link to a loco. The select below works but only shows those
> tasks where a loco is involved.:
>
[snip]

Having re-read my email and had another go, I've opted for the sub-select
approach, and come up with:

select rtid, concat(task) from
(select rtid,
case when r.rlid > 0 then
r.rcid::text || ' on ' || l.lnumber::text
else
r.rcid::text
end as task
from rides r
left outer join loco_dets l on r.rlid = l.lid) r
group by rtid
order by rtid
;

Can anyone see any problems with this, or come up with a better approach?
--
Gary Stainburn

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