Truncate (not round) decimal places in SQL Server

问题:

I\'m trying to determine the best way to truncate or drop extra decimal places in SQL without rounding. For example:

declare @value decimal(18,2)

set @value = 123.456

This will auto round @Value to be 123.46....which in most cases is good. However, for this project I don\'t need that. Is there a simple way to truncate the decimals I don\'t need? I know I can use the left() function and convert back to a decimal...any other ways?

回答1:

select round(123.456, 2, 1)

回答2:

ROUND ( 123.456 , 2 , 1 )

When the third parameter != 0 it truncates rather than rounds

http://msdn.microsoft.com/en-us/library/ms175003(SQL.90).aspx

Syntax

ROUND ( numeric_expression , length [ ,function ] )

Arguments

• 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.

回答3:

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

回答4:

Here\'s the way I was able to truncate and not round:

select 100.0019-(100.0019%.001)

returns 100.0010

And your example:

select 123.456-(123.456%.001)

returns 123.450

Now if you want to get rid of the ending zero, simply cast it:

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

returns 123.45

回答5:

Actually whatever the third parameter is, 0 or 1 or 2, it will not round your value.

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

回答6:

Round has an optional parameter

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

回答7:

Another truncate with no rounding solution and example.

    Convert 71.950005666 to a single decimal place number (71.9)
    1) 71.950005666 * 10.0 = 719.50005666
    2) Floor(719.50005666) = 719.0
    3) 719.0 / 10.0 = 71.9

    select Floor(71.950005666 * 10.0) / 10.0

回答8:

Do you want the decimal or not?

If not, use

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

If you do it with 0 then do a round:

select round(@value,2)

回答9:

This will remove the decimal part of any number

SELECT ROUND(@val,0,1)

回答10:

I know this is pretty late but I don\'t see it as an answer and have been using this trick for years.

Simply subtract .005 from your value and use Round(@num,2).

Your example:

declare @num decimal(9,5) = 123.456

select round(@num-.005,2)

returns 123.45

It will automatically adjust the rounding to the correct value you are looking for.

By the way, are you recreating the program from the movie Office Space?

回答11:

Please try to use this code for converting 3 decimal values after a point into 2 decimal places:

declare @val decimal (8, 2)
select @val = 123.456
select @val =  @val

select @val

The output is 123.46

回答12:

I think you want only the decimal value, in this case you can use the following:

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

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

回答13:

Another way is ODBC TRUNCATE function:

DECLARE @value DECIMAL(18,3) =123.456;

SELECT @value AS val, {fn TRUNCATE(@value, 2)} AS result

LiveDemo

Output:

╔═════════╦═════════╗
║   val   ║ result  ║
╠═════════╬═════════╣
║ 123,456 ║ 123,450 ║
╚═════════╩═════════╝

Remark:

I recommend using built-in ROUND function with 3rd parameter set to 1.

回答14:

I know this question is really old but nobody used sub-strings to round. This as advantage the ability to round really long numbers (limit of your string in SQL server which is usually 8000 characters):

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

回答15:

select convert(int,@value)

回答16:

Mod(x,1) is the easiest way I think.