Re: update with from

On Monday, January 23, 2012 2:00:29 am Sim Zacks wrote:
> Postgresql 8.2
>
> I want to update a table with a from that has mutliple rows joining to
> it. According to the docs, this is not advisable because:
> "If it does, then only one of the join rows will be used to update the
> target row, but which one will be used is not readily predictable."
>
> In my tests, if the joined rows are sorted it always updates with the
> first row. Does anyone have any other experiences, or should I be
> concerned that at some point it will behave differently?
>
> The performance is currently unacceptable when changing the from to only
> join to one row makes

I guess the primary question here is, what are you trying to achieve?
Do want a particular row to supply the values to the target table i.e the row
with the most timestamp?
What is the query you are using?

>
>
> Thanks
> Sim

--
Adrian Klaver
adrian(dot)klaver(at)gmail(dot)com