Nested select statements.

Question

Hi, I am writing a piece of code in which i use nested select statements for 4 tables to retrieve one column's data (ie: POSNR). But when i execute it, it takes way too long to get the data. I'm quite new to ABAP so very in need of your help. Thanks
REPORT  z_impos_test.
TABLES: coss,       "CO Object: Cost Totals for Internal Postings
        afvc,       "Operation within an order
        prps,       "WBS (Work Breakdown Structure) Element Master Data
        imzo.       "Table: CO Object - Capital Investment Prog.Pos.
TYPES: BEGIN OF st_impos,
  objnr       TYPE coss-objnr,
  gjahr       TYPE coss-gjahr,
  kstar       type coss-kstar,
  projn       type afvc-projn,
  pspnr       type prps-pspnr,
  posnr       type imzo-posnr,
END OF st_impos.
data: year TYPE coss-gjahr value '2007'.
DATA: t_output  TYPE STANDARD TABLE OF st_impos WITH HEADER LINE,
      st_output TYPE st_impos,
      t_output2 TYPE STANDARD TABLE OF st_impos WITH HEADER LINE,
      st_output2 TYPE st_impos.
SELECT objnr gjahr kstar FROM coss
INTO CORRESPONDING FIELDS OF st_output
WHERE ( objnr LIKE 'NV%' OR
      objnr LIKE 'PR%' ) AND
       gjahr = year.
   SELECT SINGLE projn from afvc into CORRESPONDING FIELDS OF st_output
       WHERE objnr = st_output-objnr.
APPEND st_output to t_output.
ENDSELECT.
SORT t_output BY objnr.
DELETE ADJACENT DUPLICATES FROM t_output.
LOOP AT t_output into st_output.
SELECT objnr pspnr
       INTO CORRESPONDING FIELDS OF st_output2
       FROM prps
       WHERE objnr = st_output-objnr
       AND   pspnr = st_output-pspnr.
  SELECT SINGLE posnr from imzo into CORRESPONDING FIELDS OF st_output2
       WHERE objnr = st_output2-objnr.
APPEND st_output2 to t_output2.
ENDSELECT.
ENDLOOP.
LOOP AT t_output2 to st_output2.
WRITE:   st_output2-posnr.
ENDLOOP.
Edited by: Jacie Johns on Apr 23, 2009 11:26 PM

Answer 1

HI John,
Try to avoid INTO CORRESPONDING FIELDS in SELECT statement.
As you are not using PSPNR and POSNR fields in the first SELECT statement. If you remove these fields, in structure, INTO CORRESPONDING FIELDS can be avoided. Create a separate structure with the fields that are required for T_OUTPUT table (i.e. create another structure with only first 4 fields, as T_OUTPUT1.
And as mentioned in your code,
  WHERE objnr = st_output-objnr
       AND   pspnr = st_output-pspnr
in select statement, ST_OUTPUT-PSPNR value is not fetched in the previous select statements.
Create Another structure with fields OBJNR, PSPNR, POSNR for table T_OUTPUT2 to store the data from tables, PRPS and IMZO.
Use JOINS and FOR ALL ENTRIES to fetch the desired data.
The sample code is as follows:
===
TYPES: BEGIN OF ty_output1,
  objnr       TYPE coss-objnr,
  gjahr       TYPE coss-gjahr,
  kstar       type coss-kstar,
  projn       type afvc-projn,
END OF ty_output1,
BEGIN OF ty_output2,
  objnr       TYPE coss-objnr,
  pspnr       type prps-pspnr,
  posnr       type imzo-posnr,
END OF ty_output2,
BEGIN OF ty_output3,
  objnr       TYPE coss-objnr,
  gjahr       TYPE coss-gjahr,
  kstar       type coss-kstar,
  projn       type afvc-projn,
  pspnr       type prps-pspnr,
  posnr       type imzo-posnr,
END OF ty_output3.
data: year TYPE coss-gjahr value '2007'.
DATA:
       wa_output1 TYPE ty_output1,   
       wa_output2 TYPE ty_output2,
       wa_output3 TYPE ty_output3,
       t_output1  TYPE STANDARD TABLE OF ty_output1 ,
       t_output2 TYPE STANDARD TABLE OF ty_output2 ,
       t_output3 TYPE STANDARD TABLE OF ty_output3..
SELECT cobjnr cgjahr ckstar aprojn FROM coss as c
     INNER JOIN afvc as A on aobjnr = cobjnr
  INTO table t_output1
  WHERE ( c~objnr like 'NV%'   or
          c~objnr like 'PR%' ) and
        c~gjahr = year.
SELECT pobjnr ppspnr i~posnr FROM prps as P
     INNER JOIN imzo AS I on pobjnr = iobjnr
     INTO TABLE t_output2
     for all entries in table T_OUTPUT1
     WHERE      p~objnr = t_output1-objnr.
SORT : t_output1 BY objnr,
            t_output2 BY objnr.
DELETE ADJACENT DUPLICATES FROM : t_output1 COMPARING objnr,
                                                                 t_output2 COMPARING objnr.
LOOP AT t_output1 INTO wa_output1
READ TABLE t_output2 INTO wa_output2 WITH KEY objnr - wa_output1-objnr BINARY SEARCH.
if sy-subrc = 0.
  MOVE <wa_output1 fiels> and <wa_output2 fields> to WA_OUTPUT3.
  append wa_output3 to T_OUTPUT3.
endif.
ENDLOOP.
Hope this will solve your problem.
Regards,
Sai Prasad