Greetings!
Having received the answer I needed to my question about using functions with
OUT parameters from this list (thanks very much!), I find myself confused about
how to use the function in a view. The function chargeneeds takes one input
parameter, a charge number, and has 3 output parameters: needsfs, needsdrygas
and needsbigbase. When I create a view, I always beginning by running the
view's select statement in pgadmin query window. I tried "select charge,
(select * from chargeneeds(charge) from charge", and got a complaint that a
subquery can only return one value. If that is so, then all this effort has
been wasted. I can use my new function in a query like this:
select charge,
(select needsfs from chargeneeds(charge)) as needsfs,
(select needsdrygas from chargeneeds(charge)) as needsdrygas,
(select needsbigbase from chargeneeds(charge)) as needsbigbase
from charge
But on the face of it, this appears to call chargeneeds(charge) three separate
times, which not only defeats the purpose of combining the three calculations
into one function, but is actually worse, because all three values will be
calculated three times.
So should I just go back to separate functions, or is PostgreSQL going to be
smart enough to optimize the three calls to chargeneeds() into a single call
internally?
Thanks again!
RobR
