Is there any funcions available to pick up first day of the month?

Question

I want to show the first month of the year given any date time stamp as input..
eg:
select sysdate from dual
assume sysdate is 10 Mar 2005
the output should be 10 Jan 2005.
We can take the last day of the month by using last_day
how to take the first day of the month given a input datetime?

Answer 1

I want to show the first month of the year given any date time stamp as input..There is a little confusion with the thread's title.
We all answered you about your title question : how to obtain the first day of month, not the first month of year. For which you can test something like this :
SQL> select col1,add_months(col1,(-1*to_char(col1,'MM'))+1)
  2  from (select to_date('10032007','DDMMYYYY') col1 from dual union all
  3*       select to_date('05012007','DDMMYYYY') col1 from dual )
SQL> /
COL1     ADD_MONT
10/03/07 10/01/07
05/01/07 05/01/07
SQL> Nicolas.