mysql - 如何优化这个删除查询？

Question

我正在尝试运行此查询:

delete FROM `customer` where customer_id 
not in (SELECT distinct customer_id FROM `order`);

但是需要很长时间，导致超时和中间中断，因为 customer 表有超过一百万条记录。

如何才能快速完成？还有其他选择吗？

编辑

这里是与 SELECT 相同的解释:

id  select_type     table   type    possible_keys   key     key_len     ref     rows    Extra   
1   PRIMARY     customer    index   NULL    PRIMARY     4   NULL    127659  Using where; Using index
2   DEPENDENT SUBQUERY  order   ALL     NULL    NULL    NULL    NULL    25141   Using where

Answer 1

尝试:

DELETE customer FROM customer t1 LEFT JOIN `order` t2 on t1.customer_id = t2.customer_id WHERE t2.customer_id is null;