相关疑难解决方法(0)

如果项目已排序,我可以运行select语句并获取行号吗？

我有这样一张桌子:

mysql> describe orders;
+-------------+---------------------+------+-----+---------+----------------+
| Field       | Type                | Null | Key | Default | Extra          |
+-------------+---------------------+------+-----+---------+----------------+
| orderID     | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| itemID      | bigint(20) unsigned | NO   |     | NULL    |                |
+-------------+---------------------+------+-----+---------+----------------+

然后我可以运行此查询以按ID获取订单数量:

SELECT itemID, COUNT(*) as ordercount
FROM orders
GROUP BY itemID ORDER BY ordercount DESC;

这给了我itemID表中每个的计数如下:

+--------+------------+
| itemID | ordercount |
+--------+------------+
|    388 |          3 |
|    234 | …