Sql server 为所有部门工作的员工的查询是什么?
对为所有部门工作的员工的查询是什么。在这里,部门和员工具有多对多的重要性 各表如下:Sql server 为所有部门工作的员工的查询是什么?,sql-server,database,Sql Server,Database,对为所有部门工作的员工的查询是什么。在这里,部门和员工具有多对多的重要性 各表如下: CREATE TABLE employees ( employee_id int NOT NULL CONSTRAINT pk_employees PRIMARY KEY, employee_name nvarchar(128) NOT NULL CONSTRAINT uk_employees_employee_name UNIQUE ); CREATE TABLE departments (
CREATE TABLE employees
(
employee_id int NOT NULL CONSTRAINT pk_employees PRIMARY KEY,
employee_name nvarchar(128) NOT NULL CONSTRAINT uk_employees_employee_name UNIQUE
);
CREATE TABLE departments
(
department_id int NOT NULL PRIMARY KEY,
department_name nvarchar(128) NOT NULL CONSTRAINT uk_departments_department_name UNIQUE
);
CREATE TABLE department_employees
(
department_id int NOT NULL CONSTRAINT fk_department_employees_departments REFERENCES departments(department_id),
employee_id int NOT NULL CONSTRAINT fk_departement_employees_employees REFERENCES employees(employee_id),
CONSTRAINT pk_deparment_employees PRIMARY KEY (department_id, employee_id)
)
样本数据:
INSERT INTO employees
VALUES (1, 'John Doe'), (2, 'Jane Doe'), (3, 'William Doe'), (4, 'Margaret Doe')
INSERT INTO departments
VALUES (1, 'Accounting'), (2, 'Humman Resources'), (3, 'Marketing')
INSERT INTO department_employees
VALUES
(1, 1), (2, 1), (3, 1),
(2, 2), (2, 3),
(3, 3), (3, 4)
预期成果:
+-------------+---------------+
| employee_id | employee_name |
+-------------+---------------+
| 1 | John Doe |
+-------------+---------------+
此操作在关系代数上称为
它可以通过如下查询在sql中实现
SELECT *
FROM dbo.employees e
WHERE
NOT EXISTS (
SELECT *
FROM departments d
WHERE d.department_id NOT IN (
SELECT dp.department_id
FROM department_employees dp
WHERE dp.department_id = d.department_id AND dp.employee_id = e.employee_id
)
)
请注意,查询:“给我所有部门工作的员工”等同于给我所有员工,即没有员工不为其工作的部门。您可以尝试下面的查询 在变量中,所有不同的部门都是从部门主表中提取的。之后,仅选择了计数与关系表中的不同链接部门计数匹配的员工
declare @distinctDeptCount int
SET @DistinctDeptCount = (SELECT Count(Distinct department_id) FROM departments)
--SELECT @DistinctDeptCount
SELECT Distinct employees.employee_id, employee_name
from employees
where employees.employee_id in (
select employee_id from department_employees GROUP BY employee_id HAVING COUNT(department_id) = @distinctDeptCount
)
或
输出如下所示
employee_id employee_name
1 John Doe
这是现场演示您可以试试这个
SELECT
emp.name
FROM
Employee emp
JOIN
EmpDept empd
ON
emp.EmployeeID = empd.EmpId
GROUP BY
emp.EmployeeID
HAVING
count(emp.EmployeeID) = (select count(1) from Department)
您需要提供所有相关表的模式和预期输出,以及示例数据和您尝试过的内容。。。EmployeeEmployeeID,Name DepartmentDeptId,Name EmpDeptId,EmpId,deptid尝试从中选择此名称。Name,counta.EmployeeID countEmp从员工a加入a.EmployeeID=b.EmpId组a.Name拥有counta.EmployeeID=从部门tmp选择count*
SELECT
emp.name
FROM
Employee emp
JOIN
EmpDept empd
ON
emp.EmployeeID = empd.EmpId
GROUP BY
emp.EmployeeID
HAVING
count(emp.EmployeeID) = (select count(1) from Department)