WHERE条件下的OpenSQL语法CASE语句

Question

我想问问是否可以将CASE语句直接写入WHERE子句（我知道WHERE子句也可以通过字符串传递），例如 

 SELECT * FROM db_table INTO TABLE @mt_table[]
     WHERE key1 = @l_key1
          AND key2 = @l_key2
          AND key3 = @l_key3
          AND key4 = @l_key4
          AND ( WHEN l_auth = 'A' THEN username = @sy-uname
                WHEN l_auth = 'U' THEN username = @sy-uname OR username = @space 
                END ). 

Answer 1

You can use OR operator in WHERE clause.

SELECT * FROM db_table INTO TABLE @mt_table[]
 WHERE key1 = @l_key1
   AND key2 = @l_key2
   AND key3 = @l_key3
   AND key4 = @l_key4
   AND ( ( l_auth = 'A' AND username = @sy-uname )
      OR ( l_auth = 'U' AND ( username = @sy-uname OR username= @space ) )
       ).

I didn't find any document for supporting case in where clause for Open Sql.