If y is omitted, x is rounded to zero decimal places.
If y is negative, x is rounded to the left of the decimal point.
The following example uses ROUND() to display the result of rounding 5.75 to zero, 1, and -1 decimal places, respectively:
SQL> SQL> SELECT ROUND(5.75), ROUND(5.75, 1), ROUND(5.75, -1) FROM dual; ROUND(5.75) ROUND(5.75,1) ROUND(5.75,-1) ----------- ------------- -------------- 6 5.8 10 SQL> SQL>