Markus Bertheau <twanger(at)bluetwanger(dot)de> writes:
> , 17.04.2004, 01:45, Tom Lane :
>> The planner sees that as "where scope = <some complicated expression>"
>> and falls back to a default estimate. It won't simplify a sub-select
>> to a constant. (Some people consider that a feature ;-).)
> Why?
It's the only way to prevent it from simplifying when you don't want it
to.
regards, tom lane