在MySQL 5.7版本中注意group的用法:
use emp;
set sql_mode='';
select x.salary,x.department_id from
(select e.* from emp e order by department_id,salary desc) x group by x.department_id;
在MySQL 5.7版本中注意group的用法:
use emp;
set sql_mode='';
select x.salary,x.department_id from
(select e.* from emp e order by department_id,salary desc) x group by x.department_id;