易错点:
1.表连接时on后面对应的字段写错
2.group by遗漏title
SELECT d.dept_no,d.dept_name,t.title,count(*) FROM departments d inner join dept_emp e on d.dept_no=e.dept_no inner join titles t on e.emp_no=t.emp_no group by d.dept_no,t.title order by d.dept_no asc
易错点:
1.表连接时on后面对应的字段写错
2.group by遗漏title
SELECT d.dept_no,d.dept_name,t.title,count(*) FROM departments d inner join dept_emp e on d.dept_no=e.dept_no inner join titles t on e.emp_no=t.emp_no group by d.dept_no,t.title order by d.dept_no asc