Hello,
You could use the LAST_DAY function to derive the first day of the month.
For ex: if you want to get the first day of the last month i.e. 01-JUN-2014 .
( The current date is 07-JULY-2014)
SELECT ADD_DAYS(LAST_DAY(ADD_MONTHS(CURRENT_DATE, -2)),1)
FROM dummy
Hope this helps.
Thanks,
Vivek Deshpande