坚持打卡和记录

从现在开始准备每日刷题和记录进程，争取早日上岸。

1789. 员工的直属部门

select employee_id, department_id
from Employee 
where primary_flag = 'Y' or employee_id in (select employee_idfrom Employeegroup by employee_idhaving count(employee_id) = 1
)