In sqlserver, the number of digits after the decimal point is retained and round is used.

Round
Returns a numeric expression rounded to the specified length or precision.

The displayed page requires that only four digits after the decimal point be retained. It is found that the number after the four decimal places can be truncated in the round (expression, 4, 1 ).
If (round, 4) is written, it indicates rounding the four digits after the decimal point, but not truncating more 0

B. Use Round And rounded approximate values

The following example shows rounding and approximate values.

Statement	Result
Select round (123.4545, 2)	123.4500
Select round (123.45,-2)	100.00

C. UseRoundTruncation

In the following example, two select statements are used to explain the difference between rounding and truncation. The first statement rounds the result. The second statement truncates the result.

Statement	Result
Select round (150.75, 0)	151.00
Select round (150.75, 0, 1)	150.00