# Round Natural Numbers to the nearest Power of 10

• Comments posted to this topic are about the item Round Natural Numbers to the nearest Power of 10

• Why do you not use the build in ROUND function?
It takes three parameters:
- the value
- the rounding length (use negative numbers to round to a power of 10, example for 12345: -1 ->  = 12350, -2  -> 12300, -3 = 12000
- optional 0 or 1, while the default 0 rounds, while 1 will cut the numbers off; `ROUND(12345, -1, 0) = 12350` while `ROUND(12345, -1, 1) = 12340`

The only benefit of your function is the easier usage of the direction (up or down), but this could be solved by cutting off the decimals (= rounding down) and adding 10 (or 100 or 1000...) when you want to round up: `ROUND(12345, -1, 1) + 10`

PS: Bonus points for using an INLINE TABLE VALUE function instead of a scalar function

God is real, unless declared integer.

• Your function has a problem when it's used against negative numbers. I wrote an article some time ago about this options which simulate CEILING and FLOOR. You can read it in here: http://www.sqlservercentral.com/articles/T-SQL/145448/
s
Here's a corrected version for your function
`CREATE FUNCTION dbo.udf_RoundNearest(@Number bigint, /*Natural Number*/@RoundNearest float, /*Power of 10, 10^n , 10,100,1000...*/@Direction int /* 0-> Down , 1 -> Up */)RETURNS TABLE AS RETURNSELECT CASE WHEN @Direction = 0     THEN ROUND(@Number-(.49*@RoundNearest),-LOG10(@RoundNearest))    ELSE ROUND(@Number+(.49*@RoundNearest),-LOG10(@RoundNearest))    END NumberGO`

Luis C.
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• Luis Cazares - Tuesday, May 16, 2017 6:27 AM

Your function has a problem when it's used against negative numbers. I wrote an article some time ago about this options which simulate CEILING and FLOOR. You can read it in here: http://www.sqlservercentral.com/articles/T-SQL/145448/
s
Here's a corrected version for your function
`CREATE FUNCTION dbo.udf_RoundNearest(@Number bigint, /*Natural Number*/@RoundNearest float, /*Power of 10, 10^n , 10,100,1000...*/@Direction int /* 0-> Down , 1 -> Up */)RETURNS TABLE AS RETURNSELECT CASE WHEN @Direction = 0     THEN ROUND(@Number-(.49*@RoundNearest),-LOG10(@RoundNearest))    ELSE ROUND(@Number+(.49*@RoundNearest),-LOG10(@RoundNearest))    END NumberGO`

• t.franz - Tuesday, May 16, 2017 2:56 AM

Why do you not use the build in ROUND function?
It takes three parameters:
- the value
- the rounding length (use negative numbers to round to a power of 10, example for 12345: -1 ->  = 12350, -2  -> 12300, -3 = 12000
- optional 0 or 1, while the default 0 rounds, while 1 will cut the numbers off; `ROUND(12345, -1, 0) = 12350` while `ROUND(12345, -1, 1) = 12340`

The only benefit of your function is the easier usage of the direction (up or down), but this could be solved by cutting off the decimals (= rounding down) and adding 10 (or 100 or 1000...) when you want to round up: `ROUND(12345, -1, 1) + 10`

PS: Bonus points for using an INLINE TABLE VALUE function instead of a scalar function

Thanks!

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