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The $TRUNC function returns a numeric expression truncated to a specified number of digits to the right of the decimal point.
If the value specified by n is positive and longer than the digits after the decimal point, 0 is added after the fraction digits.
If the value specified by n is negative and larger than or equal to the digits before the decimal point, 0 is returned.
When a numeric expression is truncated, the trailing digits are simply dropped off. The return value is not rounded in any way.
TRUNC(expression [,n])
expression Required. The numerical expression that is to be truncated.
n Optional. n is an integer indicating the number of digits to display after the decimal point.
$TRUNC(123.4545, 2) result: 123.45
$TRUNC(123.4545, -2) result: 100
$TRUNC(123.9994, 3) result: 123.999
$TRUNC(123.9995, 3) result: 123.999