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From: Gaurav on 21 Jul 2008 03:12
ROUND

Returns a numeric expression, rounded to the specified length or precision.
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 tinyint, smallint, or int. When length is a positive number, numeric_expression is rounded to the number of decimal places 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.
Return Types

Returns the same type as numeric_expression.
Remarks

ROUND always returns a value. If length is negative and larger than the number of digits before the decimal point, ROUND returns 0.
Example Result
ROUND(748.58, -4) 0

ROUND returns a rounded numeric_expression, regardless of data type, when length is a negative number.
Examples Result
ROUND(748.58, -1) 750.00
ROUND(748.58, -2) 700.00
ROUND(748.58, -3) 1000.00

Examples
A. Use ROUND and estimates

This example shows two expressions illustrating that with the ROUND function the last digit is always an estimate.

SELECT ROUND(123.9994, 3), ROUND(123.9995, 3)
GO

Here is the result set:

----------- -----------
123.9990 124.0000

B. Use ROUND and rounding approximations

This example shows rounding and approximations.
Statement Result

SELECT ROUND(123.4545, 2) 123.4500

SELECT ROUND(123.45, -2) 100.00


C. Use ROUND to truncate

This example uses two SELECT statements to demonstrate 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





Regards
Gaurav


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