I've found that multiple simple statements often work faster then convoluted single statements.
Ivan Sergio Borgonovo wrote:
> Is there a place that gives examples of all the kind of queries
> postgresql support?
>
> Sometimes I think if there is a way to obtain a result in just one
> statement without writing a function and it would be nice to have a
> panoramic of all the strategies I could try for single statements.
>
>
> The SQL reference
> http://www.postgresql.org/docs/8.1/interactive/sql-commands.html
> isn't inspirational every time
>
> Even if it is not exactly what I'm looking for a sort of "one liner"
> as the one you find for perl, sed, awk...
>
> As an example of things the kind of things I'm looking for:
>
> update system
> set weight=subselect._avg
> from (
> select round(avg(weight)) as _avg
> from system where type='module'
> ) as subselect
> where name='users_commerce';
>
>
> thx
>