ROUND

The ROUND function rounds off a value to a specified number of decimal places. Fractions greater than or equal to .5 are rounded up. Fractions less than .5 are rounded down (truncated).

Syntax

ROUND ( expression [ , decimal-places ] )

Semantics

expression	is an expression of type DOUBLE PRECISION
decimal-places	if positive, specifies the number of decimal places to display to the right of the decimal point; if negative, specifies the number of decimal places to display to the left of the decimal point.

Notes

The ROUND function rounds off except in the case of a decimal constant with more than 15 decimal places. For example:
> SELECT ROUND(3.499999999999999); -- 15 decimal places

round

-------

3

(1 row)

The internal integer representation used to compute the ROUND function causes the fraction to be evaluated precisely and it is thus rounded down. However:

> SELECT ROUND(3.4999999999999999); -- 16 decimal places

round

-------

4

(1 row)

The internal floating point representation used to compute the ROUND function causes the fraction to be evaluated as 3.5, which is rounded up.

Examples

SELECT ROUND(3.14159, 3);

3.142

SELECT ROUND(1234567, -3);

1235000

SELECT ROUND(3.4999, -1);