+----+--------+
| id | name   |
+----+--------+
|  2 | robin  |
|  3 | jyothi |
|  1 | angel  |
+----+--------+

+----+---------+--------+
| id | hobbies | ref_id |
+----+---------+--------+
|  1 | walking |      1 |
|  2 | chating |      1 |
|  3 | reading |      2 |
|  4 | walking |      2 |
+----+---------+--------+

+----+-----------------+
| name | hobbies       |
+----+-----------------+
|  1 | walking,chating |
|  3 | reading,surfing |
+----+-----------------+

select name, group_concat(hobbies) as all_hobbies
from test1,test2
where test1.id = test2.ref_id
and test1.id in (select ref_id
              from test2
              where hobbies = 'walking')
group by name

select name, group_concat(hobbies) as all_hobbies
from test1,test2
where test1.id = test2.ref_id and test1.name = 'robin'
group by name
having all_hobbies like '%walking%'

having all_hobbies like '%walking%' or
name like '%robin%'