rendered paste body+----+--------------------+----------------+-----------------+--------------------+------------+---------+----------------------+--------+--------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+--------------------+----------------+-----------------+--------------------+------------+---------+----------------------+--------+--------------------------+
| 1 | PRIMARY | a | ALL | MerchantID | NULL | NULL | NULL | 169870 | Using where |
| 1 | PRIMARY | b | ref | PRIMARY,MerchantID | MerchantID | 4 | product.a.MerchantID | 1 | |
| 2 | DEPENDENT SUBQUERY | Cat_919_Search | unique_subquery | PRIMARY,SearchStr | PRIMARY | 4 | func | 1 | Using index; Using where |
+----+--------------------+----------------+-----------------+--------------------+------------+---------+----------------------+--------+--------------------------+