Is it POWER function and FLOAT limitation ?

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Is it POWER function and FLOAT limitation ?

davidku

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Points: 1256
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April 2, 2014 at 6:40 pm

#306046

Hi,
I am just wondering why
SELECT POWER(2.718, -34.08)
returns me 0.
Tested it in Microsoft Excel
=2.718^-34.08
and it is returning me 1.58774E-15 which is approximate 15 decimal points.
My table column defined as FLOAT which can take up to 54.
Is it the limitation in the POWER function ?
Thanks.

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SQLRNNR SSC Guru Points: 281334 More actions · Answer 1

It is a limitation in Power.

SELECT POWER(2,34)

Produces

Msg 232, Level 16, State 3, Line 1
Arithmetic overflow error for type int, value = 17179869184.000000.

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davidku Ten Centuries Points: 1256 More actions · Answer 2

Geez... found the solution myself.

By default, POWER function will follow the data type from the first argument.

http://technet.microsoft.com/en-us/library/ms174276.aspx

By defining 2.718 as a FLOAT and use a variable to call the POWER function, it returns me the results I want.

Dwain Camps SSC Guru Points: 86908 More actions · Answer 3

davidku (4/2/2014)
Geez... found the solution myself.
By default, POWER function will follow the data type from the first argument.
http://technet.microsoft.com/en-us/library/ms174276.aspx
By defining 2.718 as a FLOAT and use a variable to call the POWER function, it returns me the results I want.

Or you can just use the (nearly) exact value for e:

SELECT POWER(EXP(1),-34.08);

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