Oracle SQL: the Essential Reference

TRUNC

TRUNC (n [,m])

Truncates a number to a specific number of decimal places.

Parameters

n

Specifies a number to be truncated.

m

Specifies the number of decimal places to preserve in the result. Truncating all decimal places is the default. Negative values for m result in digits being truncated to the left of the decimal point.

Example

SQL> SELECT TRUNC(99.99), TRUNC(99.99,1), TRUNC(99.99,-1)
  2  FROM dual;

TRUNC(99.99) TRUNC(99.99,1) TRUNC(99.99,-1)
------------ -------------- ---------------
          99           99.9              90

This function truncates at the specified number of decimal places and does not perform rounding.