Thanks,
my real function is quite expensive, so I don't want it to execute
twice. Toms subselect query is therefore exactly what I want, and since
it will be hidden in a view, it doesn't matter that it is a long expression.
Best regards,
Heiko
Tom Lane wrote:
regression=# select x,y,(f).* from
regression-# (select *, sum_n_product(x,y) as f from myvals offset 0) ss;
x | y | sum | prod
---+---+-----+------
1 | 2 | 3 | 2
(1 row)
The "offset 0" is an optimization fence to keep the planner from
flattening this form into the form where the function is called twice.
(As of 8.2, you can dispense with that if the function is marked volatile.)
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