Si desea utilizar el redondeo bancario en SQL Server...
CREATE FUNCTION BankersRounding(@value decimal(36,11), @significantDigits INT)
RETURNS MONEY
AS
BEGIN
-- if value = 12.345 and signficantDigits = 2...
-- base = 1000
declare @base int = power(10, @significantDigits + 1)
-- roundingValue = 12345
declare @roundingValue decimal(36,11) = floor(abs(@value) * @base)
-- roundingDigit = 5
declare @roundingDigit int = @roundingValue % 10
-- significantValue = 1234
declare @significantValue decimal(36,11) = floor(@roundingValue / 10)
-- lastSignificantDigit = 4
declare @lastSignificantDigit int = @significantValue % 10
-- awayFromZero = 12.35
declare @awayFromZero money = (@significantValue + 1) / (@base / 10)
-- towardsZero = 12.34
declare @towardsZero money = @significantValue / (@base / 10)
-- negative values handled slightly different
if @value < 0
begin
-- awayFromZero = -12.35
set @awayFromZero = ((-1 * @significantValue) - 1) / (@base / 10)
-- towardsZero = -12.34
set @towardsZero = (-1 * @significantValue) / (@base / 10)
end
-- default to towards zero (i.e. assume thousandths digit is 0-4)
declare @rv money = @towardsZero
if @roundingDigit > 5
set @rv = @awayFromZero -- 5-9 goes away from 0
else if @roundingDigit = 5
begin
-- 5 goes to nearest even number (towards zero if even, away from zero if odd)
set @rv = case when @lastSignificantDigit % 2 = 0 then @towardsZero else @awayFromZero end
end
return @rv
end
