Duilio,

dili> this is a recursive SP I found in the net:

<SNIP>

Honestly, it does not strike me as an example of how to write one...

dili> In order to understand better how SPs work, I tried to modify the
dili> code, so to get

dili> 5
dili> 20
dili> 60
dili> 120

dili> i.e. to have the result returned at every call.

This is not the way it works; the partial results are 1, 2, 6, 24,
120. Here is your original procedure a little reworked to accomplish
the task:

CREATE PROCEDURE FACTORIAL(NUM INTEGER)
RETURNS (N_FACTORIAL NUMERIC(18, 0))
AS
BEGIN
if (num = 1) THEN
n_factorial = 1;
ELSE BEGIN
for select n_factorial from FACTORIAL(:num - 1) into :n_factorial do begin
suspend;
n_factorial = :n_factorial * :num;
end
END
SUSPEND;
END

I'm sure others on this list can do better, though.

dili> PS temporary tables make a too easy solution...

And unneeded, too.
Ciao
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