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))

Round有一个可选参数

Select round(123.456, 2, 1)  will = 123.45
Select round(123.456, 2, 0)  will = 123.46

SELECT Cast(Round(123.456,2,1) as decimal(18,2))

我知道这有点晚了，但我不认为这是一个答案，我已经使用这个技巧很多年了。

只需从值中减去0.005并使用Round(@num,2)。

你的例子:

declare @num decimal(9,5) = 123.456

select round(@num-.005,2)

返回123.45

它会自动调整四舍五入到您正在寻找的正确值。

顺便问一下，你是在重现电影《办公空间》里的程序吗?

这将删除任何数字的小数部分

SELECT ROUND(@val,0,1)