Re: Setting a default value for a select statement without results

This solution gave me the result I need, but it seems the process takes
longer when COALESCE is added.

What do you mean with the comment of "and you are happy with its performance"
?
Does it have to do with performance?

Regards,
Jorge Maldonado

On Tue, Feb 5, 2013 at 10:07 PM, Jasen Betts <jasen(at)xnet(dot)co(dot)nz> wrote:

> On 2013-02-06, JORGE MALDONADO <jorgemal1960(at)gmail(dot)com> wrote:
> > --f46d0401fb2fcb805e04d50354b1
> > Content-Type: text/plain; charset=ISO-8859-1
> >
> > I have an UPDATE query with the following general structure:
> >
> > UPDATE table1 SET (SELECT field FROM table2 WHERE conditions ORDER BY
> > order_field LIMIT 1)
>
> assuming you mean this, and you are happy with its performance.
>
> UPDATE table1 SET field1 = (SELECT field FROM table2 WHERE conditions
> ORDER BY
> order_field LIMIT 1)
>
>
> > Is it possible to assign a default value in case no results are returned
> by
> > the SELECT statement?
>
> use coalesce.
>
> UPDATE table1 SET field1 = coalesce( (SELECT field FROM table2 WHERE
> conditions ORDER BY
> order_field LIMIT 1) , default_value )
>
>
>
>
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