1.

 1  DELETE FROM demo_expressions.
 2  
 3  INSERT demo_expressions FROM TABLE @( VALUE #( 
 4      ( id = 'X'
 5        char1 = ' 0123'
 6        char2 = ' 4567'  ) ) ).
 7   
 8  SELECT SINGLE
 9              char1 as text1,
10              char2 as text2,
11              concat( char1,char2 )     AS concat,
 
12              length( char1 )              AS length,      "字串長度，包含空格長度
13              "從左邊去除字串的字串，類似SHIFT LEFT DELETING LEADING 'N'
14              ltrim( char1,' ' )             AS ltrim,
15              replace( char1,'12','__')  AS replace,    "替換
16              right( char1,3 )              AS right,        "
 
從字串右邊擷取，且包含空格
17              rtrim( char1,'3')             AS rtrim,        "從右邊去除字串
18              substring( char1,3,3 )    AS substring
19              FROM demo_expressions
20              INTO @DATA(result).
21 
22 cl_demo_ouput=>write( result).