小编tar*_*rma的帖子

我有两个表：search_criteria和pricing。

表中的列和表中的search_id列都有一个索引。search_criteriapricing_idpricing

但是运行这个嵌套查询不会在search_criteria表上使用索引。

explain 
select *  
from  search_criteria USE INDEX (idx_search_id) 
where  search_id in 
    (select search_id 
    from pricing
     where pricing_id = '009330be-d041-444f-a624-ca652f3f61ed');


+----+--------------------+---------------------+------+------------------------------+----------------+---------+-------+----------+-------------+
| id | select_type        | table               | type | possible_keys                | key            | key_len | ref   | rows     | Extra       |
+----+--------------------+---------------------+------+------------------------------+----------------+---------+-------+----------+-------------+
|  1 | PRIMARY            | search_criteria | ALL  | NULL                         | NULL           | NULL    | NULL  | 19582252 | Using where |
|  2 …