SELECT '''' || CAST('123' AS CHAR(10)) || '''' from rdb$database
UNION ALL SELECT '''' || CAST('123       ' AS CHAR(10)) || '''' from rdb$database
UNION ALL SELECT '''' || '123       ' || '''' from rdb$database;

F_1

'123       '

'123       '

'123       '

          SELECT '''' || CAST('123' AS CHAR(10)) || ''''
UNION ALL SELECT '''' || CAST('123       ' AS CHAR(10)) || ''''
UNION ALL SELECT '''' || '123       ' || '''';

?column?

'123'

'123'

'123       '