Using internal table & Loop VS. select & EndSelect

[Former Member]

Hi,

Please help me to know which selection is better:

option 1:

    SELECT MAX( LETZTZUG ) MAX( LETZTABG ) MAX( LETZTVER ) MAX( LETZTBEW )

    INTO   table lt_dates

    FROM   S032

    WHERE  VRSIO = '000'

      AND  matnr = lwa_output-IDNRK

      AND  werks = lwa_output-werks.

    loop at lt_dates into lwa_dates.

      IF lwa_dates_max-LETZTZUG < lwa_dates-LETZTZUG.

        lwa_dates_max-LETZTZUG = lwa_dates-LETZTZUG.

      ENDIF.

      IF lwa_dates_max-LETZTABG < lwa_dates-LETZTABG.

        lwa_dates_max-LETZTABG = lwa_dates-LETZTABG.

      ENDIF.

      IF lwa_dates_max-LETZTVER < lwa_dates-LETZTVER.

        lwa_dates_max-LETZTVER = lwa_dates-LETZTVER.

      ENDIF.

      IF lwa_dates_max-LETZTBEW < lwa_dates-LETZTBEW.

        lwa_dates_max-LETZTBEW = lwa_dates-LETZTBEW.

      ENDIF.

    ENDLOOP.

Option 2:

    SELECT MAX( LETZTZUG ) MAX( LETZTABG ) MAX( LETZTVER ) MAX( LETZTBEW )

    INTO (lwa_output-LETZTZUG , lwa_output-LETZTABG , lwa_output-LETZTVER , lwa_output-LETZTBEW )

    FROM   S032

    WHERE  VRSIO = '000'

      AND  matnr = lwa_output-IDNRK

      AND  werks = lwa_output-werks.

Thanks.

[SharathYaralkattimath]

option 1

[Former Member]

Hi Sharath

can you explain the reason please?

[SharathYaralkattimath]

Please read ABAP documentation , this is basics that we should get the data at one go into table, & then you can process the internal table as per your needs.

[former_member189631]

Hi Arieh,

The first option queries the table and get the data from db only once.

The second option queries the table and get the data from the db in multiple times.

In ABAP program we should try to reduce the db hits as much as possible to improve the performance of the application. In your case, the first option is more efficent than second option when there is more data on the table.

Ram

[Clemenss]

The professional answer is:

It depends.

And I don't understand your code:

Option 1 with SELECT MAX... means to put the load on the database (which is almost always slower than the ABAP runtime processor). So why then loop at the table to determine max. values?

AND: Never use a LOOP INTO workarea, always use LOOP ASSIGNING <field-symbol> for the sake of performance.

SELECT ... ENDSELECT is better than people say. It saves you memory and the performance is enhanced by the system by reading blocks of data into invisible internal tables and processing them between SELECT and ENDSELECT.

If you don't write another SELECT between SELECT and ENDSELECT, then everything is fine.

Regards

Clemens