Re: can these queries be combined into one? - Mailing list pgsql-general

From Tom Molesworth
Subject Re: can these queries be combined into one?
Date
Msg-id 4F70634E.7020502@audioboundary.com
Whole thread Raw
In response to can these queries be combined into one?  (hamann.w@t-online.de)
List pgsql-general
Hi,

On 25/03/12 08:16, hamann.w@t-online.de wrote:
> I am currently doing something like
>
> select ordercode, descr, codes into temp table x from products where ...
> Here codes is a bit-mapped field
> update x set codes = codes | 512 from othertable t where ordercode = t.ordercode and ....
> select * from x
>
> Is there a way to avoid that temp table?

You just want to map some of the values in the codes field to different
values? If so, case/when should help, something like:

select ordercode, descr, case when ordercode = t.ordercode and .... then
codes | 512 else codes end as "codes" from products where ...

Note this is a read-only operation - some of the other answers seemed to
be updating the base tables, although maybe that's what you wanted?

cheers,

Tom


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