ROUND(<NumericExpression> [TO <IntegerExpression>])
ROUND(<NumericExpression> [, <IntegerExpression>])

<NumericExpression> =

Type of:

SMALLINT
INTEGER|INT
BIGINT
FLOAT
DECIMAL|NUMERIC

<IntegerExpression> =

Type of:

SMALLINT
INTEGER|INT
BIGINT

Same as input

 The ROUND function performs "normal" rounding where the number is rounded up if the fractional portion beyond the number of decimal places being rounded to is greater than or equal to 5 and down if the fractional portion is less than 5. Also, if using the ROUND function with DOUBLE PRECISION or FLOAT values, it is possible to encounter rounding errors due to the nature of floating-point values and their inability to accurately express certain fractional real numbers.

SELECT SUM(ROUND(Distance TO 2)) AS ApproxDistance
FROM Destinations