ROUND and TRUNC

ROUND and TRUNC
 
ROUND (n1, n2)
Perform rounding for n1 according to n2. n2 is 0 by default, that is, the n1 is rounded up. If n2 is a positive number, it is rounded up from n2 to the right of the n1 decimal point. If n2 is a negative number, then, it is rounded to the left n2 digit of the n1 decimal point.
 
SQL> select round (3456.6543), round (3456.6543, 2), round (3456.6543,-2) from dual;
 
ROUND (3456.6543) ROUND (3456.6543, 2) ROUND (3456.6543,-2)
-----------------------------------------------------
3457 3456.65 3500
 
TRUNC (n1, n2)
TRUNC is similar to ROUND, but TRUNC does not perform rounding and only performs bitwise truncation.
 
SQL> select trunc (3456.6543), trunc (3456.6543, 2), trunc (3456.6543,-2) from dual;
 
TRUNC (3456.6543) TRUNC (3456.6543, 2) TRUNC (3456.6543,-2)
-----------------------------------------------------
3456 3456.65 3400
 
Author: "To_Be_Monster_Of_IT"