Oracle, Make date time's first day of its month

Question

I have a datevariable, I would like to have convert it to first day of its monh,

• Eg: 10/10/2010 -> 01/10/2010
• Eg: 31/07/2010 -> 01/07/2010

Answer 1

SQL> select to_date('31/07/2010', 'DD/MM/YYYY') from dual;

TO_DATE('
---------
31-JUL-10

SQL> select trunc(to_date('31/07/2010', 'DD/MM/YYYY'), 'MM') from dual;

TRUNC(TO_
---------
01-JUL-10

SQL>