ERROR 1091 (42000): Can't DROP 'created_date'; check that column/key exists mysql&gt; alter table bill_item add  index idx_comp(created_date,product_id);
Query OK, 0 rows affected, 1 warning (1 min 2.62 sec)
Records: 0  Duplicates: 0  Warnings: 1


Trying to drop the index: 

mysql&gt; alter table bill_item drop index created_date;
ERROR 1091 (42000): Can't DROP 'created_date'; check that column/key exists
If you want to drop the index that you created previously, the correct statement would be: 

alter table bill_item drop index idx_comp;

created_date is the name of one of the columns in your table bill_item.

Note: To find the index name use 
SHOW INDEXES FROM &lt;table&gt; if you used a different naming convention than prepending 'idx_'