mysql中的排名

CREATE TABLE `tmp` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `sal` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;

+----+-----+
| id | sal |
+----+-----+
|  1 | 100 |
|  2 | 300 |
|  3 | 200 |
|  4 | 200 |
+----+-----+

mysql> select t1.id,(select t3.sal from tmp t3 where t1.id=t3.id) sal,count(t2.sal)+1 `rank` from tmp t1 left join tmp t2 on t1.sal<t2.sal group by t1.id order by `rank`;
+----+-----+------+
| id | sal | rank |
+----+-----+------+
|  2 | 300 |    1 |
|  3 | 200 |    2 |
|  4 | 200 |    2 |
|  1 | 100 |    4 |
+----+-----+------+
4 rows in set (0.06 sec)

mysql>

select *,rank() over (order by sal) as 'rank' from sal;

+----+-----+------+
| id | sal | rank |
+----+-----+------+
|  2 | 300 |    1 |
|  3 | 200 |    2 |
|  4 | 200 |    2 |
|  1 | 100 |    4 |
+----+-----+------+