ABAP Keyword Documentation → ABAP − Reference → Processing External Data → ABAP Database Access → ABAP SQL → ABAP SQL - Operands and Expressions → ABAP SQL - SQL Expressions sql_exp → sql_exp - sql_case → sql_exp - sql_simple_case
SQL Expressions, Simple CASE
This example demonstrates simple case distinctions in SQL expressions.
Other versions: 
 7.31 | 7.40 | 7.54
Source Code
    DELETE FROM demo_expressions.
    INSERT demo_expressions FROM TABLE @( VALUE #(
      ( id = 'x' char1 = 'aaaaa' char2 = 'bbbbb' )
      ( id = 'y' char1 = 'xxxxx' char2 = 'yyyyy' )
      ( id = 'z' char1 = 'mmmmm' char2 = 'nnnnn' ) ) ).
    DATA(else) = 'fffff'.
    SELECT id, char1, char2,
           CASE char1
             WHEN 'aaaaa' THEN ( char1 && char2 )
             WHEN 'xxxxx' THEN ( char2 && char1 )
             ELSE @else
           END AS text
           FROM demo_expressions
           INTO TABLE @DATA(results).
    cl_demo_output=>display( results ).
Description
In a list of columns specified after SELECT, 
CASE is used to make a simple case distinction for the content of a column. The result is a character string chained from column content or taken from a
host variable. Using the alias name defined
after AS, the result is assigned to the column with the same name in an internal table declared inline, results.