Re: conditional aggregates

Hello

use a CASE statement

http://www.postgresql.org/docs/7.4/static/functions-conditional.html

Regards

Pavel Stehule

2010/12/8 Marcin Krawczyk <jankes(dot)mk(at)gmail(dot)com>:
> Hi list,
> Can anyone advise me on creating an aggregate that would take additional
> parameter as a condition ? For example, say I have a table like this
> id;value
> 1;45
> 2;13
> 3;0
> 4;90
> I'd like to do something like this
> SELECT min_some_cond_aggregate(value,0) FROM table
> to get the minimal value from table greater than 0, in this case 13.
> I can't do SELECT min(value) FROM table WHERE value > 0 as this will mess my
> other computations. My current solution involves a function operating on the
> output of array_accum from the docs, but I'm looking for more elegant
> solution.
> Is this possible at all ? I'm running 8.1.
>
> regards
> mk
>