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# T-SQL ROUND(decimal, int) vs C# Round(Decimal, Int32)

 P: n/a Anybody noticed that SQL Server rounds up if the value is half way between two rounded values, but C#'s Decimal.Round(Decimal,Int32) rounds to nearest even number? From MSDN: "When d is exactly halfway between two rounded values, the result is the rounded value that has an even digit in the far right decimal position. For example, when rounded to two decimals, the value 2.345 becomes 2.34 and the value 2.355 becomes 2.36. This process is known as rounding toward even, or rounding to nearest." I perform the same calculation sometimes on the web server in C# and sometimes at the database in T-SQL, but want to get the same result from both calculations. Could anybody offer any strategies for dealing with this? Thanks ~ Matt Jan 30 '06 #1
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 P: n/a I would be interested to hear what the veterans in this group have to say about this one also. I use Report Builder for our reports and forms and it uses Delphi Pascal. This variant of Pascal uses the rounding to even also. Makes for interesting reports when SQL does one side of the equation (like a subtotal + tax + shipping) and Pascal does the grand total, it's quite possible to end up with 100.01 + 0 + 0 = 100.00 (SQL value + SQL value + SQL value = Pascal value) Gabe Jan 30 '06 #2

 P: n/a On 30 Jan 2006 08:42:43 -0800, Matt wrote: Anybody noticed that SQL Server rounds up if the value is half waybetween two rounded values, but C#'s Decimal.Round(Decimal,Int32)rounds to nearest even number?From MSDN: "When d is exactly halfway between two rounded values, theresult is the rounded value that has an even digit in the far rightdecimal position. For example, when rounded to two decimals, the value2.345 becomes 2.34 and the value 2.355 becomes 2.36. This process isknown as rounding toward even, or rounding to nearest."I perform the same calculation sometimes on the web server in C# andsometimes at the database in T-SQL, but want to get the same resultfrom both calculations. Could anybody offer any strategies for dealingwith this? Hi Matt, This method of rounding is called "bankers rounding". Here's a link to a previous discussion about it, including some techniques to do this in SQL Server (warning - long URL, might wrap) http://groups.google.com/group/micro...e9e40e0a7f6f32 -- Hugo Kornelis, SQL Server MVP Jan 30 '06 #3

 P: n/a Matt (ma********@gmail.com) writes: Anybody noticed that SQL Server rounds up if the value is half way between two rounded values, but C#'s Decimal.Round(Decimal,Int32) rounds to nearest even number?From MSDN: "When d is exactly halfway between two rounded values, the result is the rounded value that has an even digit in the far right decimal position. For example, when rounded to two decimals, the value 2.345 becomes 2.34 and the value 2.355 becomes 2.36. This process is known as rounding toward even, or rounding to nearest." Unbelievable! I thought that this was just something that was taught out of a whim for a while in Swedish schools when I was a kid. (Since long replaced. A colleague who's 15 years younger than me was completely baffled when she heard of the concept.) I perform the same calculation sometimes on the web server in C# and sometimes at the database in T-SQL, but want to get the same result from both calculations. Could anybody offer any strategies for dealing with this? Write your own rounding function in any of the languages. If you are on SQL 2000, it be may be better for performance to do it in C#. If you are on SQL 2005, you would still do it in C#, but you could use the function in SQL Server. In fact, we have done something of the kind, although our problem was different. We needed to round floating-point numbers "intelligently". -- Erland Sommarskog, SQL Server MVP, es****@sommarskog.se Books Online for SQL Server 2005 at http://www.microsoft.com/technet/pro...ads/books.mspx Books Online for SQL Server 2000 at http://www.microsoft.com/sql/prodinf...ons/books.mspx Jan 30 '06 #4

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