0

我有

employees table(id,f_name,l_name,salary,dept_id,manager_id)

departments table(id,dept_name,manager_id)

我想在单个表格中显示dept_name其manager_id、经理l_name和在各自经理下工作的员工人数。

4

5 回答 5

2

尝试这个：

SELECT dept.dept_name, dept.manager_id, emp.l_name, emp_count.empcount 
FROM departments AS dept 
INNER JOIN (SELECT COUNT(*) AS empcount, manager_id FROM employees GROUP BY manager_id) AS emp_count ON dept.manager_id = emp_count.manager_id
INNER JOIN employees AS emp ON dept.manager_id = emp.id

或这个：

SELECT dept.dept_name, dept.manager_id, emp.l_name, emp_count.empcount 
FROM departments AS dept 
INNER JOIN (SELECT COUNT(*) AS empcount, dept_id FROM employees GROUP BY manager_id) AS emp_count ON dept.dept_id = emp_count.dept_id
INNER JOIN employees AS emp ON dept.manager_id = emp.id

第一个是引用manager_id，第二个是引用dept_id。两者中的任何一个都可以得到相同的结果。我通过为员工人数创建一个子查询并将其链接到部门来实现这一点。

这是SQL Server 2008 小提琴。

于 2013-07-11T05:30:37.333 回答
0

你可以通过一个简单的查询来做到这一点，但是你应该删除employees表中的manager_id，只使用员工记录id作为标识符。

Select dept.dept_name, dept.manager_id, (select e.l_name from employees as e where e.id = dept.manager_id), count(select em.id from employees as em where dept.id = em.dept_id) FROM departments as dept

但是，这应该可以工作，您没有提供您正在使用的特定数据库。如果您更新您的问题或告诉什么数据库，如果它不起作用，我可以编辑该数据库。

于 2013-07-11T03:55:05.993 回答
0

correlated subquery您可以通过计数来实现这一点。休息你可以选择使用加入。这可能会帮助你

 SELECT  D.dept_name,
            D.manager_id,
            E.l_name,
            (SELECT COUNT(*) 
                     FROM employees 
                     WHERE manager_id=D.manager_id) AS numberOfEmployees
 FROM   departments D INNER JOIN employees E ON D.manager_id=E.id
于 2013-07-11T05:49:26.773 回答
0

检查这个

    select d.deptname, d.managerid, e.fname, (select COUNT(*) 
                                            from employees 
                                            where managerid = d.managerid and 
                                            managerid <> id and
                                            depid = d.id
                                            group by managerid) NoofEmps
from departments d join employees e on d.managerid = e.id

字段名称可能与您提到的不完全相同。

于 2013-07-11T04:12:28.363 回答
-1

这是您可以考虑的另一种解决方案

SELECT D.dept_name as [Department Name],
E.manager_id as [Manager ID],
E.l_name as [Last Name],
(SELECT COUNT(*) FROM employees EM WHERE EM.manager_id = E.id) as [Employee Count]
FROM departments D
INNER JOIN employees E on D.manager_id = E.manager_id
于 2013-07-11T09:08:07.457 回答