mysql> create table test(id int, txt varchar(8));
Query OK, 0 rows affected (0.82 sec)

mysql> insert into test (id, txt)
    -> select 1,'11,22'
    -> union all
    -> select 2,'33,44,55';
Query OK, 2 rows affected (0.17 sec)
Records: 2  Duplicates: 0  Warnings: 0

mysql> select * from test;
+------+----------+
| id   | txt      |
+------+----------+
|    1 | 11,22    |
|    2 | 33,44,55 |
+------+----------+
2 rows in set (0.00 sec)

mysql> select distinct id,
    ->        substring_index(substring_index(txt, ',', num), ',', -1) word
    -> from test,
    -> (      select 1 num
    ->  union select 2
    ->  union select 3
    ->  union select 4
    ->  union select 5
    -> ) numbers
    -> order by 1,2;
+------+------+
| id   | word |
+------+------+
|    1 | 11   |
|    1 | 22   |
|    2 | 33   |
|    2 | 44   |
|    2 | 55   |
+------+------+
5 rows in set (0.01 sec)