Question

此查询要求MySQL从product表返回项目。我希望按照IN子句中的顺序返回结果。

select id, price 
from product 
where id IN (5552902, 5552737, 5552887, 5549436, 5552291, 5552897, 
             5550834, 5552794, 5548666, 5552621);

+---------+----------+
| id      | price    |
+---------+----------+
| 5548666 | 919.0000 |
| 5549436 | 939.0000 |
| 5550834 | 919.0000 |
| 5552291 | 939.0000 |
| 5552621 | 829.0000 |
| 5552737 | 999.0000 |
| 5552794 | 919.0000 |
| 5552887 | 999.0000 |
| 5552897 | 939.0000 |
| 5552902 | 999.0000 |
+---------+----------+

由于某种原因，MySQL在不遵守订单的情况下返回结果，我必须使用ORDER BY price DESC才能获得所需的结果。

select id, price 
from product 
where id IN (5552902, 5552737, 5552887, 5549436, 5552291, 
             5552897, 5550834, 5552794, 5548666, 5552621) 
ORDER BY price DESC;

+---------+----------+
| id      | price    |
+---------+----------+
| 5552902 | 999.0000 |
| 5552887 | 999.0000 |
| 5552737 | 999.0000 |
| 5552291 | 939.0000 |
| 5549436 | 939.0000 |
| 5552897 | 939.0000 |
| 5550834 | 919.0000 |
| 5552794 | 919.0000 |
| 5548666 | 919.0000 |
| 5552621 | 829.0000 |
+---------+----------+

MySQL版本为5.6。我想知道为什么MySQL不会以“正确”的顺序返回项目。

Answer 1

如果您想保留in clause中的订单，可以使用order by field某些内容

select 
id, price from product 
where id IN (5552902, 5552737, 5552887, 5549436, 5552291, 5552897, 5550834, 5552794, 5548666, 5552621)
order by field(id,5552902, 5552737, 5552887, 5549436, 5552291, 5552897, 5550834, 5552794, 5548666, 5552621)
;

为什么MySQL不按IN子句中出现的顺序返回行？

1 个答案: