我有一个带有InnoDB表的MySQL数据库,总计超过10个GB的数据,我想从MysqL 5.5迁移到MysqL 5.7.我有一个看起来有点像的查询：

SELECT dates.date,count(mySub2.myColumn1),sum(mySub2.myColumn2)
FROM (
    SELECT date
    FROM dates -- just a table containing all possible dates next 5 years
    WHERE date BETWEEN '2016-06-01' AND '2016-09-03'
) AS dates
LEFT JOIN (
    SELECT o.id,time_start,time_end
    FROM order AS o
    INNER JOIN order_items AS oi on oi.order_id = o.id
    WHERE time_start BETWEEN '2016-06-01' AND '2016-09-03'
) AS mySub1 ON dates.date >= mySub1.time_start AND dates.date < mySub1.time_end
LEFT JOIN (
    SELECT o.id,time_end
    FROM order AS o
    INNER JOIN order_items AS oi on oi.order_id = o.id
    WHERE o.shop_id = 50 AND time_start BETWEEN '2016-06-01' AND '2016-09-03'
) AS mySub2 ON dates.date >= mySub2.time_start AND dates.date < mySub2.time_end
GROUP BY dates.date;

我的问题是这个查询在MysqL 5.5中执行速度很快,但在MysqL 5.7中速度极慢.

在MysqL 5.5中,它首先花费超过1秒并且<每次重复执行0.001秒而不重启MysqL.
在MysqL 5.7中,它最初需要11.5秒,每次重复执行需要1.4秒而不重启MysqL.
我添加到查询中的LEFT JOIN越多,查询在MysqL 5.7中就越慢.

这两个实例现在在同一台计算机上,在同一个硬盘驱动器上运行,并且具有相同的my.ini设置.所以它不是硬件.
执行计划确实有所不同,但我不知道该怎么做.

这是MysqL 5.5上的EXPLAIN EXTENDED：

| id | select_type | table      | type  | possible_keys | key         | key_len | ref       | rows  | filtered | extra                           |
|----|-------------|------------|-------|---------------|-------------|---------|-----------|-------|----------|---------------------------------|
| 1  | PRIMARY     | dates      | ALL   |               |             |         |           | 95    | 100.00   | Using temporary; Using filesort |
| 1  | PRIMARY     | 

| id | select_type | table | type   | possible_keys | key         | key_len | ref              | rows | filtered | extra          |
|----|-------------|-------|--------|---------------|-------------|---------|------------------|------|----------|----------------|
| 1  | SIMPLE      | dates | ALL    |               |             |         |                  | 95   | 100.00   | Using filesort |
| 1  | SIMPLE      | oi    | ref    | xxxxxx        | order_id_fk | 4       | const            | 228  | 100.00   |                |
| 1  | SIMPLE      | o     | eq_ref | xxxxx         | PRIMARY     | 4       | myDb.oi.order_id | 1    | 100.00   | Using where    |
| 1  | SIMPLE      | o     | ref    | xxxx          | shop_id_fk  | 4       | const            | 65   | 100.00   | Using where    |
| 1  | SIMPLE      | oi    | ref    | xxx           | order_id_fk | 4       | myDb.o.id        | 1    | 100.00   | Using where    |