Math.Round in C# and Sql Server

Question

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Does math.round in C# and sql server are the same.
I have check the following, but I didn't understand how the Math.Round function is working in C#.
Sql Server:
select convert(varchar,convert(numeric(18,2),224.025000000 )) Output 224.03

C#:
Math.Round(224.025000000)) Output 224.02
But
Math.Round(2.345, 2) Output 2.35
Math.Round(2.245, 2) Output 2.24

Can anybody tell Why the outputs of above two statements are different ?

Thanks in advance.

Posted 11-Aug-11 19:47pm

Gopi9999

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Comments

Henry.Ayoola 12-Aug-11 3:30am

Short answer: because the inputs are different. numeric(18,2) isn't the same type as double.

3 solutions

Solution 3

From MSDN (http://msdn.microsoft.com/en-us/library/75ks3aby.aspx[^]):
Notes to Callers
Because of the loss of precision that can result from representing decimal values as floating-point numbers or performing arithmetic operations on floating-point values, in some cases the Round(Double, Int32) method may not appear to round midpoint values to the nearest even value in the digits decimal position. This is illustrated in the following example, where 2.135 is rounded to 2.13 instead of 2.14. This occurs because internally the method multiplies value by 10 * digits, and the multiplication operation in this case suffers from a loss of precision.

Posted 11-Aug-11 20:22pm

Wendelius

Solution 1

Hi Gopi,

Please use ROUND (Transact-SQL) to achive this.

Posted 11-Aug-11 20:04pm

Liju Sankar

Comments

Gopi9999 12-Aug-11 2:11am

Hi, Thanks for reply.
Even if I use Round, I am facing the same problem
select round(224.025,2) Output 224.030 and it is rounding to 224.02 in c#.
I want both values to be equal. What to do...

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Prerak Patel · Accepted Answer · 2011-08-11T20:14:00

Solution 2

Use this

C#

Math.Round(224.02500000, 2,MidpointRounding.AwayFromZero)

Ref:http://msdn.microsoft.com/en-us/library/system.midpointrounding.aspx[^]

Posted 11-Aug-11 20:14pm

Prerak Patel

Comments

Gopi9999 12-Aug-11 2:22am

Thank you very much. It solved my problem...

Prerak Patel 12-Aug-11 2:24am

You are welcome.