Update Purchase Order number.(Link GL to PO)

Question

Hi all,
Currently i am using the below query for one of our report(R12). However there is a need to update Purchase Order Number .Could anyone please help on how to link GL to PO and provide the updated query.The query is as follows.
SELECT gjl.je_line_num,
    gjl.code_combination_id,
    SUM(NVL(GJL.accounted_dr, 0))                                     AS Accounted_DR,
    SUM(NVL(GJL.accounted_cr, 0))                                     AS Accounted_CR,
    ( SUM(NVL(GJL.accounted_dr, 0)) - SUM(NVL(GJL.accounted_cr, 0)) ) AS Accounted_Balance,
    gjb.actual_flag,
    NULL     AS "Check Number",
    gjb.name AS "Batch Name",
    TO_CHAR(gjh.currency_conversion_date, 'DD-Mon-YYYY') currency_conversion_date,
    ROUND(gjh.CURRENCY_CONVERSION_RATE,4) CURRENCY_CONVERSION_RATE,
    gjh.currency_conversion_type,
    NULL                                                          AS Document_Number,
    SUM(NVL(GJL.entered_dr, 0))                                   AS Entered_DR,
    SUM(NVL(GJL.entered_cr, 0))                                   AS Entered_CR,
    ( SUM(NVL(GJL.entered_dr, 0)) - SUM(NVL(GJL.entered_cr, 0)) ) AS Entered_Balance,
    gcc.segment1
    || '.'
    || gcc.segment2
    || '.'
    || gcc.segment3
    || '.'
    || gcc.segment4
    || '.'
    ||gcc.segment5
    || '.'
    || gcc.segment6
    || '.'
    || gcc.segment7
    || '.'
    || gcc.segment8 "Account Code",
    gl.currency_code AS "Ledger Currency",
    gjh.name         AS "Header Name",
    gjl.description  AS "Journal Line Description",
    NULL             AS party_name,
    NULL             AS party_id,
    GJH.period_name,
    TO_CHAR(gjh.POSTED_DATE, 'DD-Mon-YYYY') POSTED_DATE,
    NULL AS "Purchase Invoice Number",
    NULL AS "AP Invoice Line Description",
    NULL AS "Sales Invoice Number",
    gcc.segment1 Company ,
    gcc.segment2 Account,
    DECODE(gcc.segment2,NULL,'',apps.gl_flexfields_pkg.get_description_sql(gcc.chart_of_accounts_id,2,gcc.segment2)) AS "Seg2 Desc",
    gcc.segment3 AS "Business Model",
    gcc.segment4 Region,
    gcc.segment5 AS "Cost Profit Center",
    gcc.segment6 AS "Product Group",
    gcc.segment7 AS "Related Company",
    gcc.segment8 AS "Reserve",
    gjl.status   AS "Journal Line Status",
    GL.name      AS "LEDGER NAME",
    GJH.currency_code,
    GJH.je_category je_cat_f,
    GJCT.user_je_category_name je_category,
    GJH.je_source,
    NULL AS "Sales_order" ,
    NULL AS "Purchase Order Number"
  FROM APPS.gl_je_headers gjh,
    APPS.gl_je_batches gjb,
    APPS.gl_ledgers gl,
    APPS.gl_je_lines gjl,
    APPS.gl_code_combinations gcc,
    (SELECT je_category_name,
      user_je_category_name
    FROM APPS.GL_JE_CATEGORIES_TL
    WHERE language='E'
    ) GJCT
  WHERE gjh.je_from_sla_flag IS NULL
  --AND gjh.EXTERNAL_REFERENCE IS NULL
  AND gjb.je_batch_id         = gjh.je_batch_id
  AND gjh.ledger_id           = gl.ledger_id
  AND gjh.je_header_id        = gjl.je_header_id
  AND gcc.code_combination_id = gjl.code_combination_id
  AND GJH.JE_CATEGORY         = GJCT.je_category_name(+)
  AND GL.name NOT IN('NL ABX RepCorp USD (EUR)')
  GROUP BY gjl.je_line_num,
    gjl.code_combination_id,
    gjb.actual_flag,
    gjb.name,
    gjh.currency_conversion_date,
    ROUND(gjh.CURRENCY_CONVERSION_RATE,4),
    gjh.currency_conversion_type,
    gcc.segment1
    || '.'
    || gcc.segment2
    || '.'
    || gcc.segment3
    || '.'
    || gcc.segment4
    || '.'
    ||gcc.segment5
    || '.'
    || gcc.segment6
    || '.'
    || gcc.segment7
    || '.'
    || gcc.segment8,
    gl.currency_code,
    gjh.name,
    gjl.description,
    gjb.je_batch_id,
    gjb.status,
    gjb.posted_date,
    gjb.description,
    gl.name,
    gjh.name,
    GJH.period_name,
    gjh.posted_date,
    gcc.segment1,
    gcc.segment2,
    gcc.segment3,
    gcc.segment4,
    gcc.segment5,
    gcc.segment6,
    gcc.segment7,
    gcc.segment8,
    GL.name,
    gjl.status,
    GJH.je_category,
    GJCT.user_je_category_name,
    GJH.je_source,
    GJH.currency_code,
    DECODE(gcc.segment2,NULL,'',apps.gl_flexfields_pkg.get_description_sql(gcc.chart_of_accounts_id,2,gcc.segment2))

Answer 1

Finally Resolved the problem by writing 2 exits.
one exit 'EXIT_SAPLVEDB_007'  for identify correct item in the sales order by updating the customer purchase order item number i.e., VBAP-POSEX.  if we update the POSEX field then it wont create new item instead, it will update the item which it is referring to .
2nd exit for updating the purchase order number. 
I have tried to pass the program name, screen number, field name, field value etc to bdcdata in the exit 'EXIT_SAPLVEDB_002'. but I observed that it is not going to that screen in the debugging.
when I try E1EDP02 with QUALF '044' it will update ship-to party's purchase order number.  so to update ship-to party's purchase order number it is going to that screen. 
so I have used that thing to update purchase order number in sold-to party's purchase order number.
so when it is going that screen iam changing the field name 'VBKD-BSTKD_E' to 'VBKD-BSTKD' in bdcdata.  Then it is worked.
This is the solution I found in my time.
Any way it is solved.  Hope it will be helpful for others who will get this problem.