Oracle Finding first day of the month

Hi

Following sql helps you to find first day of previous months.


select  trunc(sysdate) from dual

22.01.2016

First Day of Current Month:
select    ADD_MONTHS (   LAST_DAY (  TRUNC (SYSDATE)  )  ,   -1  )+1   from dual

01.01.2016                                                                    

First Day of  eleven months before:                                      
select    ADD_MONTHS (   LAST_DAY (  TRUNC (SYSDATE)  )  ,   -11  )+1   from dual

01.03.2015