create table employee
(emp_id integer not null,
manager_id integer not null,
emp_name char(20) not null,
emp_tel char(10),
emp_salary number not null,
hire_date date,
constraint pk_employee primary key(emp_id)
);
alter table employee
add constraint fk_employee_manager foreign key(manager_id)
references employee(emp_id);
查找拥有5名以上员工的经理的ID
任何帮助如何解决此查询????
只需这样做:您需要使自己熟悉分组功能的可能性
select manager_id
from employee
group by manager_id
having count(*)>5
insert into employee (emp_id, manager_id, emp_name, emp_salary)
select 1, 1, 'A', 1000 from dual
union select 2, 1, 'A', 1000 from dual
union select 3, 1, 'A', 1000 from dual
union select 4, 1, 'A', 1000 from dual
union select 5, 1, 'A', 1000 from dual
union select 6, 1, 'A', 1000 from dual
union select 7, 2, 'A', 1000 from dual;
select manager_id, count(emp_id) from employee group by manager_id
having count(emp_id) > 5;