我的桌子：
mysql> select * from professor;
+-------+--------+--------+--------+------+
| empid | name | status | salary | age |
+-------+--------+--------+--------+------+
| 1 | Arun | 1 | 2000 | 23 |
| 2 | Benoy | 0 | 3000 | 25 |
| 3 | Chacko | 1 | 1000 | 36 |
| 4 | Divin | 0 | 5000 | 32 |
| 5 | Edwin | 1 | 2500 | 55 |
| 7 | George | 0 | 1500 | 46 |
+-------+--------+--------+--------+------+
6 rows in set (0.00 sec)
mysql> select * from works;
+----------+-------+---------+
| courseid | empid | classid |
+----------+-------+---------+
| 1 | 1 | 10 |
| 2 | 2 | 9 |
| 3 | 3 | 8 |
| 4 | 4 | 10 |
| 5 | 5 | 9 |
| 6 | 1 | 9 |
| 2 | 3 | 10 |
| 2 | 1 | 7 |
| 4 | 2 | 6 |
| 2 | 4 | 6 |
| 2 | 5 | 2 |
| 7 | 5 | 6 |
| 3 | 5 | 2 |
| 6 | 4 | 10 |
+----------+-------+---------+
14 rows in set (0.00 sec)
mysql> select * from course;
+----------+------------+--------+
| courseid | coursename | points |
+----------+------------+--------+
| 1 | Maths | 5 |
| 2 | Science | 1 |
| 3 | English | 6 |
| 4 | Social | 4 |
| 5 | Malayalam | 20 |
| 6 | Arts | 25 |
| 7 | Biology | 20 |
+----------+------------+--------+
7 rows in set (0.00 sec)
问题是：
返回教授人数最多的教授的姓名
第10类课程
我试过的查询是：
select professor.name,works.courseid,works.empid,works.classid from professor
inner join works
on professor.empid=works.empid
where works.classid=10
group by works.courseid
我知道它不完整/不正确。请帮助我达到所需的结果。
最佳答案
select
professor.name, count(works.courseid)
from
works
inner join
professor on
professor.empid = works.empid
where
work.classid = 10
group by
professor.name
order by count(works.courseid) desc
limit 1
关于mysql - 使用mysql中的联接获取所需的数据，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/21486073/