Rounds May 25, 2005, to the first day in the nearest month

 
SQL>
SQL> SELECT ROUND(TO_DATE('25-MAY-2005'), 'MM') FROM dual;

ROUND(TO_
---------
01-JUN-05

SQL>
SQL>

1.	ROUND: Returns the number rounded to nearest value (precision adjustable)
2.	Syntax: ROUND(,)
3.	Specifying negative precision will round numbers on the left side of the decimal point, as shown here:
4.	ROUND(5.75)
5.	Simple demo for ROUND: round a number
6.	ROUND with precision
7.	ROUND(44.647, -1)
8.	ROUND(Number,1): round values from column
9.	ROUND(Number,0)
10.	ROUND(Number,-1)
11.	Round an AVG function
12.	Use ROUND function in PL/SQL
13.	round Demo
14.	Round date to day
15.	Round price as new price
16.	Round result from months_between
17.	Rounding Up and Down
18.	Rounds 7:45:26 P.M. on May 25, 2005, to the nearest hour

Rounds May 25, 2005, to the first day in the nearest month : ROUND « Numeric Math Functions « Oracle PL / SQL