Обсуждение: Casting issue with aggregated function
Hi,
I'm facing a cast issue when using sub queries and I 'd like your opinion if this should be submittede as a Bug.
(Postgres version 8.1.0)
Compare:
A)
select sum(25665800) as c
=> 25665800 (int8)
B)
select sum(c) from
(
select sum(25665800) as c
)foo
=> 25665800 (numeric)
I find the cast form int8 to numeric being strange.
Cheers,
Marc
On Mon, Jan 02, 2006 at 11:18:53AM +0100, Marc Mamin wrote: > select sum(c) from > ( > select sum(25665800) as c > )foo > > => 25665800 (numeric) > > I find the cast form int8 to numeric being strange. It's documented to work that way: http://www.postgresql.org/docs/8.1/interactive/functions-aggregate.html The return type for sum() is "bigint for smallint or int arguments, numeric for bigint arguments, double precision for floating-point arguments, otherwise the same as the argument data type." Your subquery has an integer argument so its sum() returns bigint; you then feed that bigint to sum() so the result is numeric. Presumably the promotions are done to avoid overflow. -- Michael Fuhr