How to make Dynamic Query in Oracle

SELECT

            DISTINCT

            gcc.&segments code,

            gcc.&detail_segments nat_account,

            (case when &detail_segments=segment1 then w_dev_pkg.GET_COMPANY_DESC(gcc.code_combination_id)

                  when &detail_segments=segment2 then w_dev_pkg.GET_BUSINESS_DESC(gcc.code_combination_id)

                  when &detail_segments=segment3 then w_dev_pkg.GET_COST_CENTER_DESC(gcc.code_combination_id)

                  when &detail_segments=segment4 then W_DEV_PKG.GET_NATURAL_DESC(gCC.CODE_COMBINATION_ID)

                  when &detail_segments=segment5 then W_DEV_PKG.GET_Product_DESC(gCC.CODE_COMBINATION_ID)

                  when &detail_segments=segment6 then W_DEV_PKG.GET_CUSTOMER_DESC(gCC.CODE_COMBINATION_ID)

                  when &detail_segments=segment7 then w_dev_pkg.GET_Spare1_DESC(gcc.code_combination_id)

                  when &detail_segments=segment8 then w_dev_pkg.GET_Spare2_DESC(gcc.code_combination_id)

              end ) nat_acct_des,

            (case when &segments=segment1 then w_dev_pkg.GET_COMPANY_DESC(gcc.code_combination_id)

                  when &segments=segment2 then w_dev_pkg.GET_BUSINESS_DESC(gcc.code_combination_id)

                  when &segments=segment3 then w_dev_pkg.GET_COST_CENTER_DESC(gcc.code_combination_id)

                  when &segments=segment4 then W_DEV_PKG.GET_NATURAL_DESC(gCC.CODE_COMBINATION_ID)

                  when &segments=segment5 then W_DEV_PKG.GET_Product_DESC(gCC.CODE_COMBINATION_ID)

                  when &segments=segment6 then W_DEV_PKG.GET_CUSTOMER_DESC(gCC.CODE_COMBINATION_ID)

                  when &segments=segment7 then w_dev_pkg.GET_Spare1_DESC(gcc.code_combination_id)

                  when &segments=segment8 then w_dev_pkg.GET_Spare2_DESC(gcc.code_combination_id)

              end ) fLEXdESCRIPTION,

--       round(nvl(gb.begin_balance_dr- gb.begin_balance_cr, 0) ,0) openingBal,

       sum(jel.entered_dr) enter_dr,

       sum(jel.entered_cr) enter_cr,

       sum(nvl(jel.accounted_dr,0)) acdr,

       sum(nvl(jel.accounted_cr,0))  accr

--       (gb.begin_balance_dr- b.begin_balance_cr)+nvl(jel.entered_dr,0)-nvl(jel.entered_cr,0) activity,

FROM

                         gl_je_batches jeb,

                         gl_je_headers jeh,

                         gl_je_lines   jel,

                         gl_code_combinations gcc

                   

WHERE

                              jeb.je_batch_id=jeh.je_batch_id

      AND                     jeh.je_header_id=jel.je_header_id

      AND                     jel.code_combination_id=gcc.code_combination_id

      AND                     jeb.status = (case when :bstatus = 'P' then 'P' when :bstatus = 'U' then 'U' else jeb.status end)

      AND                     jeh.default_effective_date between NVL(:from_date,jeh.default_effective_date) and NVL(:To_date, jeh.default_effective_date)    

      AND                     jeh.SET_OF_BOOKS_ID=0000

      AND                     jeh.actual_flag='A'

      AND                      gcc.&segments between :code_from and :code_to

group by

                              gcc.&segments,   

                             (case  when &segments=segment1 then w_dev_pkg.GET_COMPANY_DESC(gcc.code_combination_id)

                                    when &segments=segment2 then w_dev_pkg.GET_BUSINESS_DESC(gcc.code_combination_id)

                                    when &segments=segment3 then w_dev_pkg.GET_COST_CENTER_DESC(gcc.code_combination_id)

                                    when &segments=segment4 then W_DEV_PKG.GET_NATURAL_DESC(gCC.CODE_COMBINATION_ID)

                                    when &segments=segment5 then W_DEV_PKG.GET_Product_DESC(gCC.CODE_COMBINATION_ID)

                                    when &segments=segment6 then W_DEV_PKG.GET_CUSTOMER_DESC(gCC.CODE_COMBINATION_ID)

                                    when &segments=segment7 then w_dev_pkg.GET_Spare1_DESC(gcc.code_combination_id)

                                    when &segments=segment8 then w_dev_pkg.GET_Spare2_DESC(gcc.code_combination_id)

                               end ),

                                 gcc.&detail_segments,

                            (case when &detail_segments=segment1 then w_dev_pkg.GET_COMPANY_DESC(gcc.code_combination_id)

                                     when &detail_segments=segment2 then w_dev_pkg.GET_BUSINESS_DESC(gcc.code_combination_id)

                                     when &detail_segments=segment3 then w_dev_pkg.GET_COST_CENTER_DESC(gcc.code_combination_id)

                                     when &detail_segments=segment4 then W_DEV_PKG.GET_NATURAL_DESC(gCC.CODE_COMBINATION_ID)

                                     when &detail_segments=segment5 then W_DEV_PKG.GET_Product_DESC(gCC.CODE_COMBINATION_ID)

                                     when &detail_segments=segment6 then W_DEV_PKG.GET_CUSTOMER_DESC(gCC.CODE_COMBINATION_ID)

                                     when &detail_segments=segment7 then w_dev_pkg.GET_Spare1_DESC(gcc.code_combination_id)

                                     when &detail_segments=segment8 then w_dev_pkg.GET_Spare2_DESC(gcc.code_combination_id)

                            end )

  

 ORDER BY  nat_account