ABAP_to_the_Future

2
New Language Features in ABAP 7.4
Tip
In the SQL version of GROUP BY, you can only use column names. Because the internal
table version of GROUP BY is processed wholly within ABAP, you can do all sorts of
groovy things in addition—comparison, method calls, and the like, for example:
LOOP AT lt_monsters INTO DATA( ls_monsters )
GROUP BY( type = ls_monsters-type
crackers = is_it_mad( ls_monsters-number )
ASSIGNING FIELD-SYMBOLS( <ls_monster_group> ).
This takes quite a bit of experimentation before you get comfortable with it. The most
difficult part, as with all of these new constructs, is marrying new abilities to real-world
problems, such as the customer open item example presented earlier.
2.6.9 Extracting One Table from Another
There are two new ways of extracting on e internal table from another that were
introduced with 7.4, and both use the constructor operator FILTER. The next subsection
will talk first about using the FILTER operator with conditional logic and
then as a FOR ALL ENTRIES operation on an internal table.
FILTER with Conditional Logic
To understand the process of extracting one table from another in ABAP 7.4,
return to the monsters example. Once again, you have a big table of all the monsters,
and you want to extract a smaller internal table with just the averagely mad
monsters. Normally, you would just loop through the big table and append lines
to your new table, as shown in Listing 2.65.
LOOP AT lt_all_monsters INTO ls_all_monsters
WHERE sanity > 25
AND sanity < 75.
CLEAR ls_averagely_mad_monsters.
MOVE-CORRESPONDING ls_all_monsters TO ls_averagely_mad_monsters.
APPEND ls_averagely_mad_monsters TO lt_averagely_mad_monsters.
ENDLOOP. "All Monsters
Listing 2.65 Extracting One Table from Another before 7.4
As of ABAP 7.4 (SP 8), you can do the same thing by using the constructor operator
FILTER in the fashion shown in Listing 2.66.
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