ROUND ( 123.456 , 2 , 1 )

当第三个参数!= 0时，它截断而不是舍入。

语法

ROUND ( numeric_expression , length [ ,function ] )

参数

numeric_expression Is an expression of the exact numeric or approximate numeric data type category, except for the bit data type. length Is the precision to which numeric_expression is to be rounded. length must be an expression of type tinyint, smallint, or int. When length is a positive number, numeric_expression is rounded to the number of decimal positions specified by length. When length is a negative number, numeric_expression is rounded on the left side of the decimal point, as specified by length. function Is the type of operation to perform. function must be tinyint, smallint, or int. When function is omitted or has a value of 0 (default), numeric_expression is rounded. When a value other than 0 is specified, numeric_expression is truncated.

实际上，不管第三个参数是0或1或2，它不会四舍五入你的值。

CAST(ROUND(10.0055,2,0) AS NUMERIC(10,2))

你到底要不要小数点?

如果没有，请使用

select ceiling(@value),floor(@value)

如果你用0做，那么做一轮:

select round(@value,2)

我认为你只需要小数， 在这种情况下，你可以使用以下方法:

declare @val decimal (8, 3)
SET @val = 123.456

SELECT @val - ROUND(@val,0,1)

我知道这个问题非常古老，但没有人使用子字符串舍入。这是对很长的数字进行四舍五入的优势(SQL server中字符串的限制通常是8000个字符):

SUBSTRING('123.456', 1, CHARINDEX('.', '123.456') + 2)

以下是我能够截断而不是舍入的方法:

select 100.0019-(100.0019%.001)

返回100.0010

你的例子是:

select 123.456-(123.456%.001)

返回123.450

现在，如果你想去掉0结尾，只需对它进行强制转换:

select cast((123.456-(123.456%.001)) as decimal (18,2))

返回123.45