Programming

SQL> select sysdate from dual;

SYSDATE
---------
06-AUG-11

SQL> select trunc(trunc(sysdate,'MM')-1,'MM') "First Day of Last Month" from dual;

First Day
---------
01-JUL-11

SQL> select trunc(sysdate,'MM')-1 "Last Day of Last Month" from dual;

Last Day
---------
31-JUL-11

SQL>

test@ORA11G>
test@ORA11G>
test@ORA11G> select sysdate as today,
 2         trunc(add_months(sysdate,-1),'mm') as prev_mnth_first_day,
 3         last_day(add_months(sysdate,-1))   as prev_mnth_last_day
 4  from dual
 5  /
 
TODAY     PREV_MNTH_FIRST_DAY  PREV_MNTH_LAST_DAY
--------- -------------------- --------------------
21-AUG-11 01-JUL-11            31-JUL-11
 
test@ORA11G>
test@ORA11G>