ABAP Keyword Documentation → ABAP - Reference → Processing Internal Data → Internal Tables → Processing Statements for Internal Tables → LOOP AT itab → LOOP AT itab - GROUP BY → Examples of Grouping with LOOP
Internal Tables, Grouping with LOOP in Control Levels
This example demonstrates simple control level processing using GROUP BY.
Other versions:
7.31 | 7.40 | 7.54
Source Code
DATA itab TYPE HASHED TABLE OF line
WITH UNIQUE KEY col1 col2.
DATA(out) = cl_demo_output=>new( ).
itab = VALUE #(
FOR j = 1 UNTIL j > 3
( col1 = 'A'
col2 = j
col3 = j ** 2 )
( col1 = 'B'
col2 = 2 * j
col3 = ( 2 * j ) ** 2 ) ).
out->write( itab )->line( ).
DATA sum TYPE line.
DATA total TYPE line.
DATA group LIKE itab.
LOOP AT itab ASSIGNING FIELD-SYMBOL(<line>)
GROUP BY <line>-col1 ASCENDING.
CLEAR sum.
CLEAR group.
LOOP AT GROUP <line> INTO DATA(line).
group = VALUE #( BASE group ( line ) ).
sum = sum( EXPORTING line = line
base = sum ).
ENDLOOP.
out->write( group )->line( )->write( sum )->line( ).
total = sum( EXPORTING line = sum
base = total ).
ENDLOOP.
total-col1 = '*'.
out->line( )->write( total )->display( ).
Description
This example works in the same way as the example for
control level processing. Here, the
group key is constructed
explicitly using the value of the column col1 and, unlike in control level processing, does not depend on the structure of the table and its sorting.
The statement SUM is replaced by a functional method that replaces the implicit behavior of the statement with an explicit and self-defined function.
group and sum could also be filled by the evaluation
of a table comprehension or table reduction using FOR ... IN GROUP, instead of in a
member loop LOOP AT GROUP:
FOR line IN GROUP <line>
NEXT s = sum( EXPORTING line = line
base = s ) ).
group = #( FOR <wa> IN GROUP <line> ( <wa> ) ).
The example for grouping with FOR demonstrates how the entire group loop can be implemented using expressions.