Consider I have a table like this.
+-------------+---------------+----------------+---------------+ + id + column 1 + column 2 + column 3
use FIND_IN_SET() -- a builtin function for mysql to search a string
FIND_IN_SET()
SELECT * FROM tableName WHERE column 1 = 'values' and FIND_IN_SET('a',column 3 )>0
sample
REFER