Hello,
I've got the following situation:
select expensive_function(table) from table
where expensive_function(table) is not null;
Is there a way to avoid that expensive_function is evaluated twice (if it's
not null) ?
I've tried stuff like immutable, but that doesn't do anything for me.
Of course I can do a select into, but my guess is it would be even more
expensive than evaluating these functions twice.
Thanks in advance,
Han Holl