例子，mysql查询中获取行号。
复制代码 代码示例:
mysql> describe orders;
+-------------+---------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------+---------------------+------+-----+---------+----------------+
| orderID | bigint(20) unsigned | NO | PRI | NULL | auto_increment |
| itemID | bigint(20) unsigned | NO | | NULL | |
+-------------+---------------------+------+-----+---------+----------------+
通过Id返回查询结果行号：
复制代码 代码示例:
SELECT itemID, COUNT(*) as ordercount
FROM orders
GROUP BY itemID ORDER BY ordercount DESC;
输出结果：
+--------+------------+
| itemID | ordercount |
+--------+------------+
| 388 | 3 |
| 234 | 2 |
| 3432 | 1 |
| 693 | 1 |
| 3459 | 1 |
+--------+------------+
获了指定范围的记录数据，带行号：
复制代码 代码示例:
mysql> SET @rank=0;
Query OK, 0 rows affected (0.00 sec)
mysql> SELECT @rank:=@rank+1 AS rank, itemID, COUNT(*) as ordercount
-> FROM orders
-> GROUP BY itemID ORDER BY rank DESC;
+------+--------+------------+
| rank | itemID | ordercount |
+------+--------+------------+
| 5 | 3459 | 1 |
| 4 | 234 | 2 |
| 3 | 693 | 1 |
| 2 | 3432 | 1 |
| 1 | 388 | 3 |
+------+--------+------------+
5 rows in set (0.00 sec)
修改查询语句为：
复制代码 代码示例:
SET @rank=0;
SELECT @rank:=@rank+1 AS rank, itemID, COUNT(*) as ordercount
FROM orders
GROUP BY itemID
ORDER BY ordercount DESC;
另外的写法，未做测试：
复制代码 代码示例:
SELECT @rn:=@rn+1 AS rank, itemID, ordercount
FROM (
SELECT itemID, COUNT(*) AS ordercount
FROM orders
GROUP BY itemID
ORDER BY ordercount DESC
) t1, (SELECT @rn:=0) t2;
