如何编写 MySQL 查询来检测丢失（缺席）记录？

Question

我被一个复杂的 MySQL 查询困住了。我有以下表格：

[employee]
id
name

[department]
id
name

[employee_department_relation]
id
employee_id
department_id

[attendance]
id
employee_id
date

注意：只有当员工在该日期在场时，才会记录出勤率。没有为旷工设置特定标志。

我需要查明，在特定日期哪个部门有多少员工缺勤。

到目前为止，我已经按照 SQL 完成了，但它并不完美：

SELECT A.date, 
(SELECT name FROM employee WHERE id = emp_id) AS employee,
(SELECT D.name AS dept_name
 FROM deptartment D
 INNER JOIN employee_department_relation R ON R.dept_id = D.id
 INNER JOIN employee E ON E.id = R.emp_id
 WHERE R.emp_id = A.emp_id
 ) AS dept
FROM attendance A
WHERE A.date = '2014-07-03'

我该如何继续？

Answer 1

随意尝试这个更改日期：

select employee.name, department.name from employee
left join employee_department_relation r on r.employee_id = employee.id
left join department on department.id = r.department_id
where employee.id not in (
    select employee_id from attendance where date = '2014-07-28'
)