作业20200506

2.完成下列分组查询练习题(以课上建表代码为参考)
1. 查询岗位名以及岗位包含的所有员工名字
select post as '岗位', group_concat(name) as '员工' from emp group by pos
t;

2. 查询岗位名以及各岗位内包含的员工个数

select post, count(id) from emp group by post;

3. 查询公司内男员工和女员工的个数

select sex, count(id) from emp group by sex;

4. 查询岗位名以及各岗位的平均薪资

select post, avg(salary) as avg_salary from emp group by post;

5. 查询岗位名以及各岗位的最高薪资

select post, max(salary) as max_salary from emp group by post;

6. 查询岗位名以及各岗位的最低薪资

select post, min(salary) as min_salary from emp group by post;

7. 查询男员工与男员工的平均薪资，女员工与女员工的平均薪资

select group_concat(name), avg(salary) from emp group by sex;