Query GL Apps R12 Difference in two Years group by Months

Query based from the seeded report:

SELECT --'Assets' TYPE1, 

   SUM(DECODE(GB.PERIOD_NAME, :P_PERIOD_NAME, 

                                               NVL(BEGIN_BALANCE_DR,0) + NVL(PERIOD_NET_DR,0),0)

                                  - DECODE(GB.PERIOD_NAME, 'Jan-'||SUBSTR(:P_PERIOD_NAME,5,6), NVL(BEGIN_BALANCE_DR,0), 0)) DEBITS_YTD

      ,SUM(DECODE(GB.PERIOD_NAME,  :P_PERIOD_NAME,

                                               NVL(BEGIN_BALANCE_CR,0) + NVL(PERIOD_NET_CR, 0), 0)

                                         - DECODE(GB.PERIOD_NAME, 'Jan-'||SUBSTR(:P_PERIOD_NAME,5,6), NVL(BEGIN_BALANCE_CR,0), 0)) CREDITS_YTD                                

      FROM gl.gl_balances GB,gl.gl_code_combinations CC

--      APPS.FD_FIN_POLICIES_SEC PS, APPS.FD_FIN_POLICIES_ACC PA

WHERE GB.CODE_COMBINATION_ID = CC.CODE_COMBINATION_ID

--AND TO_NUMBER(PS.SECTOR) = TO_NUMBER(CC.SEGMENT1)

--AND TO_NUMBER(PA.ORACLE_ACCOUNT_CODE) = TO_NUMBER(CC.SEGMENT3)

--AND nvl(substr(PA.IMF_CODE,1,2),PA.IMF_CODE) in (22,31)

AND CC.chart_of_accounts_id = 50320

          AND CC.ENABLED_FLAG = 'Y'

          AND CC.SUMMARY_FLAG = 'N'

          AND CC.TEMPLATE_ID IS NULL

--AND (PS.COFOG >= :P_COFOG OR :P_COFOG IS NULL)

--AND (PS.COFOG <= :P_COFOGTO OR :P_COFOGTO IS NULL)

AND (GB.ledger_id  = :LEDG_ID OR :LEDG_ID IS NULL)--2091

AND (GB.code_combination_id = :CCID OR :CCID IS NULL)--26037

--AND (GB.PERIOD_YEAR = :PERIOD_YR OR :PERIOD_YR IS NULL)--2019

--AND (GB.PERIOD_NUM  >=  :PERIOD_NO OR :PERIOD_NO IS NULL)--1

--AND (GB.PERIOD_NUM  <=  :PERIOD_NOTO OR :PERIOD_NOTO IS NULL)--3

AND (CC.SEGMENT1 LIKE :SEC_NO OR :SEC_NO IS NULL)--1

AND (CC.SEGMENT3 LIKE :ACC_NO OR :ACC_NO IS NULL)--1 

AND GB.PERIOD_NUM <> 13

AND GB.Actual_flag  = 'A'

AND GB.TEMPLATE_ID IS NULL

--GROUP BY PS.COFOG

 select * from (

  select code_combination_id, PERIOD_NUM, nvl(a3.ENTERED_YEAR_TO_DATE,0) - nvl(a4.ENTERED_YEAR_TO_DATE,0) amount from (

    SELECT bal.code_combination_id,

         (  bal.begin_balance_dr_beq

          - bal.begin_balance_cr_beq

          + bal.period_net_dr_beq

          - bal.period_net_cr_beq)

             ENTERED_YEAR_TO_DATE

             ,PERIOD_NUM

             ,apps.gl_flexfields_pkg.get_concat_description

(cc.chart_of_accounts_id,

bal.code_combination_id

)code_comb_desc,

(SELECT kfv.concatenated_segments

FROM gl_code_combinations_kfv kfv

WHERE code_combination_id = bal.code_combination_id)segments

    FROM GL_CODE_COMBINATIONS cc, GL_BALANCES bal, GL_LEDGERS gl

   WHERE     (cc.SEGMENT1 >= :P_From_Sec OR :P_From_Sec IS NULL)

         AND (cc.SEGMENT1 <= :P_To_Sec OR :P_To_Sec IS NULL)

         AND (cc.SEGMENT2 >= :P_From_Dep OR :P_From_Dep IS NULL)

         AND (cc.SEGMENT2 <= :P_To_Dep OR :P_To_Dep IS NULL)

         AND (cc.SEGMENT3 >= :P_From_Acc1 OR :P_From_Acc1 IS NULL)

         AND (cc.SEGMENT3 <= :P_To_Acc1 OR :P_To_Acc1 IS NULL) 

         AND (cc.SEGMENT4 >= :P_From_Sub_Acc OR :P_From_Sub_Acc IS NULL)

         AND (cc.SEGMENT4 <= :P_To_Sub_Acc OR :P_To_Sub_Acc IS NULL)  

         AND bal.ACTUAL_FLAG = NVL ( :P_ACTUAL_FLAG, 'A')

         AND bal.CODE_COMBINATION_ID = cc.CODE_COMBINATION_ID

         AND bal.LEDGER_ID = gl.LEDGER_ID

         AND cc.CHART_OF_ACCOUNTS_ID = 50320

         AND bal.LEDGER_ID = 2091

         AND cc.TEMPLATE_ID IS NULL

AND :P_YTD_PTD = 'YTD' 

AND PERIOD_NAME IN (SELECT XXI.PERIOD_NAME FROM  XX_I_GL_PERIODS_I XXI WHERE PERIOD_ID BETWEEN :P_FROM_PERIOD AND :P_TO_PERIOD)

GROUP BY 

          PERIOD_NUM,

         (  bal.begin_balance_dr_beq

          - bal.begin_balance_cr_beq

          + bal.period_net_dr_beq

          - bal.period_net_cr_beq)

          ,apps.gl_flexfields_pkg.get_concat_description

(cc.chart_of_accounts_id,

bal.code_combination_id

),bal.code_combination_id

  ) A3

  full join (

    SELECT bal.code_combination_id,

         (  bal.begin_balance_dr_beq

          - bal.begin_balance_cr_beq

          + bal.period_net_dr_beq

          - bal.period_net_cr_beq)

             ENTERED_YEAR_TO_DATE

             ,PERIOD_NUM

             ,apps.gl_flexfields_pkg.get_concat_description

(cc.chart_of_accounts_id,

bal.code_combination_id

)code_comb_desc,

(SELECT kfv.concatenated_segments

FROM gl_code_combinations_kfv kfv

WHERE code_combination_id = bal.code_combination_id)segments

    FROM GL_CODE_COMBINATIONS cc, GL_BALANCES bal, GL_LEDGERS gl

   WHERE     (cc.SEGMENT1 >= :P_From_Sec OR :P_From_Sec IS NULL)

         AND (cc.SEGMENT1 <= :P_To_Sec OR :P_To_Sec IS NULL)

         AND (cc.SEGMENT2 >= :P_From_Dep OR :P_From_Dep IS NULL)

         AND (cc.SEGMENT2 <= :P_To_Dep OR :P_To_Dep IS NULL)

         AND (cc.SEGMENT3 >= :P_From_Acc1 OR :P_From_Acc1 IS NULL)

         AND (cc.SEGMENT3 <= :P_To_Acc1 OR :P_To_Acc1 IS NULL) 

         AND (cc.SEGMENT4 >= :P_From_Sub_Acc OR :P_From_Sub_Acc IS NULL)

         AND (cc.SEGMENT4 <= :P_To_Sub_Acc OR :P_To_Sub_Acc IS NULL)  

         AND bal.ACTUAL_FLAG = NVL ( :P_ACTUAL_FLAG, 'A')

         AND bal.CODE_COMBINATION_ID = cc.CODE_COMBINATION_ID

         AND bal.LEDGER_ID = gl.LEDGER_ID

         AND cc.CHART_OF_ACCOUNTS_ID = 50320

         AND bal.LEDGER_ID = 2091

         AND cc.TEMPLATE_ID IS NULL

AND :P_YTD_PTD = 'YTD' 

AND PERIOD_NAME IN (SELECT XXI.PERIOD_NAME FROM  XX_I_GL_PERIODS_I XXI WHERE PERIOD_ID BETWEEN :P_FROM_PERIOD_2 AND :P_TO_PERIOD_2)

GROUP BY 

          PERIOD_NUM,

         (  bal.begin_balance_dr_beq

          - bal.begin_balance_cr_beq

          + bal.period_net_dr_beq

          - bal.period_net_cr_beq)

          ,apps.gl_flexfields_pkg.get_concat_description

(cc.chart_of_accounts_id,

bal.code_combination_id

),bal.code_combination_id

  ) A4

  using(code_combination_id, PERIOD_NUM)

)

pivot (

  SUM(AMOUNT) as YTD_DIFF

  for PERIOD_NUM in (

    '1' as Jan, '2' as Feb, '3' as Mar,

    '4' as Apr, '5' as May, '6' as Jun,

    '7' as Jul, '8' as Aug, '9' as Sep,

    '10' as Oct, '11' as Nov, '12' as Dec, '13' as Adj

  )

);