Re: Select a-row alternative from several tables one-by-one until found

Dear Dirk,

Good idea. Thank you.

Rayfil.

Dirk Sudheimer wrote:

> On Tue, 30 May 2000 11:12:04 +0800, Rayfil Cheung
> <rayfil_at_forward-hk.com> wrote:
>
> >Hi friend,
> >
> >Thank you for your advice. Sorry for my vague mind. The searched
> >value(row) may be stored in one or many tables. The searched tables are
> >given the priority. Once the value(row) is found, no further tables are
> >needed to be searched.
> >
> >Thanks & Regards,
> >Rayfil.
> >
>
> Hi Rayfil,
> maybe the following approach works for you:
>
> SELECT somefield, 1 FROM TableWithHighestPriority
> UNION
> SELECT somefield, 2 FROM TableWithSecondHighestPriority
> UNION
> ...
> SELECT somefield, n FROM TableWithLeastPriority
> SORT BY 2
>
> and just use the first row returned (of course all
> tables are searched, but at least you get the values
> from the table with the highest priority).
>
> Dirk
Received on Tue May 30 2000 - 00:00:00 CDT