Re: numeric precision when raising one numeric to another.
| От | John Burger |
|---|---|
| Тема | Re: numeric precision when raising one numeric to another. |
| Дата | |
| Msg-id | f7dbed2cc9c8db8cb2cbfbcf546a38b7@mitre.org обсуждение исходный текст |
| Ответ на | Re: numeric precision when raising one numeric to another. (Tom Lane <tgl@sss.pgh.pa.us>) |
| Ответы |
Re: numeric precision when raising one numeric to another.
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| Список | pgsql-general |
>> Considering that the SQL spec says the result of multiplication of >> exact >> numeric types is exact numeric types of precision S1+S2, and >> exponentiation is nothing more than repeated multiplication, > > ... not when the exponent is non-integral. For one thing. For another, I believe the standard C library only has floating point exponentiation functions, not that there aren't plenty of numeric libraries with integral ones. Finally, exponentiated numbers get real big, real fast, and the floating point types can hold much larger magnitudes than the integer types, albeit inexactly. For example, on the Mac I'm using now, long long ints max out at about 10^19, while long doubles can represent 10^308. - John Burger MITRE
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