Re: [BUGS] agregate function sum error
От | sferac@bo.nettuno.it |
---|---|
Тема | Re: [BUGS] agregate function sum error |
Дата | |
Msg-id | Pine.LNX.3.96.980216102604.11072C-100000@nero обсуждение исходный текст |
Список | pgsql-hackers |
On Sun, 15 Feb 1998, Marin D wrote: > > Hi! > > You can try to typecast to float8 > > I have no idea how MySql is doing SUM() - probably it uses unsigned int > for SUM() so this gives u twice bigger upper limit - try it with MySql > with sum exceeding 2^32. I suppose the result will be negative ... > Well, I asked this question to MySql mailing list: > sferac> What's meaning "inf" as a result during a SUM() ? > sferac> Is it an overflow warning, and if so what's the max range of SUM() > sferac> before to have an overflow ? > > mysql> update t set myfloat=myfloat*9.1; > sferac> Query OK, 1415 rows affected (4.94 sec) > > mysql> select sum(myfloat) from t; > sferac> 1 row in set (0.04 sec) > > sferac> +--------------+ > sferac> | sum(myfloat) | > sferac> +--------------+ > sferac> | Inf | > sferac> +--------------+ > > mysqld does all normal calculation with doubles (bit functions are > done with longlong); The range of a double is typical something like: > > #define DBL_MAX 1.7976931348623157E+308 > #define DBL_MIN 2.2250738585072014E-308 > > Yours, > Monty Isn't it a good solution to implement PostgreSQL SUM() function ? What do you think about ? ____________________________Jose' Soares Da Silva_____________________________ Via Bazzanese, 69 ),,,( www.sferacarta.com Casalecchio R.(BO) Italy +|o o|+ sferac@bo.nettuno.it Fax. ++39 51 6131537 /. .\ Tel. ++39 51 591054 ---------------------------------(_---_)-------------------------------------- "...when men cease to destroy the animal race the lion and the lamb can dwell together..." (Joseph Smith)
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