我正在学习MySQL,我正在尝试在查询中进行简单的算术运算,
我正在尝试编写一个命令来确定大学每个学院中Instructors
的数量
任何人都可以帮助我吗?谢谢!
以下是我的两张表:
________________________________________________________
| Department | Faculty | Building |
--------------------------------------------------------
| Humanities | Arts and Sciences | Chardon |
| English | Arts and Sciences | Chardon |
| Mathematics | Arts and Sciences | Monzon |
| General Engineering | Engineering | Stefani |
| Agronomy | Agriculture | Pinero |
_________________________________________________________________________
| Professor | Department | Rank | Salary |
---------------------------------------------------------------------------
| Joe Blow | Biology | Professor | $73,500.00 |
| Sam Snow | Mathematics | Instructor | $45,700.00 |
| George Grow | Electrical Engineering | Associate Professor | $69,250.00 |
| Hiram Lowe | English | Assistant Professor | $63,750.00 |
答案 0 :(得分:1)
接近这一点:
select department.faculty, count(professor.professor) as instructors from department join professor on department.department = professor.department group by department.faculty
基本上你做一个联合来“合并”这两个表,然后由教师分组结果,并为每个教师计算教授。