How can I persuade this MYSQL query to use the indexes?
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14-11-2019 - |
سؤال
Below is the EXPLAIN for the query in question..
mysql> EXPLAIN SELECT orders_0.id, orders_0.created_at, orders_0.total_amount, orders_0.delivery_date, orders_0.customer_id, orders_0.items_summary, orders_0.site_id, orders_0.depot_id, orders_0.region_id, addresses_0.country, orders_0.payment_status, orders_0.created_by, orders_0.status, orders_0.delivered_by
-> FROM production.addresses addresses_0, production.orders orders_0
-> WHERE orders_0.delivery_address_id = addresses_0.id AND ((orders_0.status Not In ('cancelled','checkout','expired')) AND (orders_0.delivery_date>{d '2011-10-31'}));
+----+-------------+-------------+--------+------------------------------------------+---------+---------+-----------------------------------------------+--------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------------+--------+------------------------------------------+---------+---------+-----------------------------------------------+--------+-------------+
| 1 | SIMPLE | orders_0 | ALL | status,delivery_date,delivery_address_id | NULL | NULL | NULL | 929330 | Using where |
| 1 | SIMPLE | addresses_0 | eq_ref | PRIMARY | PRIMARY | 4 | production.orders_0.delivery_address_id | 1 | |
+----+-------------+-------------+--------+------------------------------------------+---------+---------+-----------------------------------------------+--------+-------------+
2 rows in set (0.00 sec)
mysql>
I have indexes on the three columns it's trying to do where conditions on but sadly it's not trying to use an index merge. Is the only option to create a multi-column index or is there something that's putting MYSQL off using those indexes?
المحلول
You have to create a multi-columns index.
For example, to do that in Phpmyadmin, you have to check this different fields of your table and click the 'index' button below the table structure.
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