Perfomance of select

Question

Hi , here i am using inner join for 3 data base tables in below code ,
SELECT crco~objid     "Object ID
         crco~endda     "End date
         crco~begda     "Start date
         cssl~lstar     "Activity type
         cost~tkg001    "Activity Unit price month01
         cost~tkg002    "Activity Unit price month02
         cost~tkg003    "Activity Unit price month03
         cost~tkg004    "Activity Unit price month04
         cost~tkg005    "Activity Unit price month05
         cost~tkg006    "Activity Unit price month06
         cost~tkg007    "Activity Unit price month07
         cost~tkg008    "Activity Unit price month08
         cost~tkg009    "Activity Unit price month09
         cost~tkg010    "Activity Unit price month10
         cost~tkg011    "Activity Unit price month11
         cost~tkg012    "Activity Unit price month12
    INTO TABLE i_actp
    FROM crco INNER JOIN cssl
      ON crcokostl     EQ  csslkostl
   INNER JOIN cost
      ON csslobjnr     EQ  costobjnr
   WHERE crco~objty EQ c_a.
but for this i am getting some lakhs of records so how can i implement FOR ALL ENTRIES for tis select statement ,
thx for u r help

Answer 1

FOR ALL ENTRIES clause is meant to be used when there are records in an existing internal table which you want to use for filtering out the data while selecting from a database table using a select.
you can probably first fetch data from the COST and CSSL tables and use for all entries.
assuming you have data in itab_cssl and itab_cost tables first (the cost table will be populated based on the cssl table for matching objnr...so you can use for all entries there too.
select <your field list> from cssl into table itab_cssl.
if itab_cssl[] is not initial.
select <your field list> from cost into table itab_cost for all entries in itab_cssl where objnr = itab_cssl-objnr.
endif.
if itab_cssl[] is not initial.
select <your field list> from crco into table i_actp for all entries in itab_cssl where kostl = itab_cssl-kostl and objty eq c_a.
endif.
thereafter you can remove the records which are not matching the criteria.
For your example, it depends what you want. If the table holds lakhs of records for the criteria you have specified, it will indeed return those records. If you want to filter the records then use more fields in the WHERE clause of the select query.
The ideal scenario will be to get the data by specifying all fields that are part of the primary key of the table in the where clause in an internal table and then delete the records that you don't require. (Of course, if this suits your scenario). This way it will use the primary index on the table and the performance will improve.
hope that helps....