题解 | #汇总各个部门当前员工的title类型的分配数目#

with A as(
    select e.emp_no,e.dept_no,d.dept_name  from  dept_emp e join 
departments d  on e.dept_no=d.dept_no 
),
B as
(
select A.emp_no,A.dept_no,A.dept_name,t.title  from   A join 
titles t  on A.emp_no=t.emp_no)
select B.dept_no,B.dept_name,B.title,count(title) as count from   B 
group by B.dept_no,B.title
order by B.dept_no