Re: how to do this join ? - Mailing list pgsql-sql

From Peter Eisentraut
Subject Re: how to do this join ?
Date
Msg-id Pine.LNX.4.30.0104061646190.1603-100000@peter.localdomain
Whole thread Raw
In response to how to do this join ?  (juerg.rietmann@pup.ch)
List pgsql-sql
juerg.rietmann@pup.ch writes:

> Hello there
>
> I have another SQL question. Please see the example :
>
> select *,
> (select a_typ from auftrag where a_nr=z_a_nr) as typ,
> (select a_t_definition_d from auftrags_typ where a_t_code=typ) as text
> from zylinder

select zylinder.*, auftrag.a_typ (select a_t_definition_d from auftrags_typ where a_t_code = auftrag.a_typ)
from zylinder, auftrag
where auftrag.a_nr = zylinder.z_a_nr;

or, using 7.1, maybe something like

select zylinder.*, auftrag.a_typ, auftrags_typ.a_t_definition
from (zylinder join auftrag on a_nr = z_a_nr) left join auftrags_typ on a_t_code = a_typ

Other variations are possible, depending on the referential contraints you
have between the tables.

>
> I have three tables that I need data from. I'd like to use the <as typ> to
> temporary store the kind of auftrag and then use it to get the
> definition (clear text) from another table.
>
> The query returns that typ is not known .

-- 
Peter Eisentraut      peter_e@gmx.net       http://yi.org/peter-e/



pgsql-sql by date:

Previous
From: juerg.rietmann@pup.ch
Date:
Subject: how to do this join ?
Next
From: Tom Lane
Date:
Subject: Re: how to do this join ?