But when it comes to performance, both beats each other in there own domain.

It all comes down to number of “‘matches” in the WHERE/IF-clause.

In case you have a rare match, the WHERE-method is better.
In case you have an always match, the IF-method is better.

When the match was done on 1-out-1000:

When the match was done at 1 – out of -2 :

and when the “match” is matching every line

*source = Harry Dietz

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And this the SLOWEST method to be adopted.

The next best method is accessing the right set of data, using Binary Search, and then read thru it.

(2) read table i_coep with key
kokrs = i_cobk-kokrs
belnr = i_cobk-belnr
binary search.
if sy-subrc = 0.
Loop at i_coep from sy-tabix
where kokrs = i_cobk-kokrs
and belnr = i_cobk-belnr.
…….
Endloop.
endif.

But ‘the best of the lot’ goes to the code, which is the extension of second method defined above. This code exits when no matching criteria is found and thus avoid looping thru the whole internal table.

(3) read table i_coep with key
kokrs = i_cobk-kokrs
belnr = i_cobk-belnr
binary search.
if sy-subrc = 0.
Loop at i_coep from sy-tabix.
if ( i_coep-kokrs NE i_cobk-kokrs or
i_coep-belnr NE i_cobk-belnr )
exit.
endif.
Endloop.
endif.

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