How to add month in a GL Calendar - Oracle Apps R12

 Go to General Ledger ,Vision Operation (USA) < Setup 

Then Setup < Financials < Calendars < Accounting

Query (F11) "Accounting"  then press Ctrl + F11 

 Go to File < New and add a new line Accordingly.

Enter all mandatory field as required.

Now Save 

Finally,  Month added in Calendar.

 following Query cab help  to check the status of the Period Details -

select a.period_name,

       a.period_num,

       a.gl_status,

       b.po_status,

       c.ap_status

from

   (select period_name, period_num, 

    decode(closing_status,'O','Open',

                          'C','Closed',

                          'F','Future',

                          'N','Never',

           closing_status) gl_status

    from gl_period_statuses

    where application_id = 101

    and start_date >= '01-JAN-98

    and end_date < '01-JAN-99'

    and set_of_books_id = &&set_of_books_id) a,

   (select period_name, 

    decode(closing_status,'O','Open',

                          'C','Closed',

                          'F','Future',

                          'N','Never',

           closing_status) po_status

    from gl_period_statuses

    where application_id = 201

    and start_date >= '01-JAN-15'

    and end_date < '01-JAN-16'

    and set_of_books_id = &&set_of_books_id) b,

   (select period_name,

    decode(closing_status,'O','Open',

                          'C','Closed',

                          'F','Future',

                          'N','Never',

           closing_status) ap_status

    from gl_period_statuses

    where application_id = 200

    and start_date >= '01-JAN-15'

    and end_date < '01-JAN-16'

    and set_of_books_id = &&set_of_books_id) c

where a.period_name = b.period_name

and   a.period_name = c.period_name

order by a.period_num