SQL Server T-SQL

CREATE DATABASE MyDatabase;

CREATE TABLE Employee (
    ID INT PRIMARY KEY,
    Name VARCHAR(50),
    Department VARCHAR(50)
);

SELECT * FROM Employee;

SELECT Name, Department FROM Employee;

SELECT * FROM Employee WHERE Department = 'IT';

INSERT INTO Employee (ID, Name, Department) VALUES (1, 'Alice', 'HR');

UPDATE Employee SET Department = 'Finance' WHERE Name = 'Alice';

DELETE FROM Employee WHERE Name = 'Alice';

CREATE PROCEDURE GetEmployees
AS
BEGIN
    SELECT * FROM Employee;
END;

CREATE TRIGGER AuditEmployee
ON Employee
AFTER INSERT
AS
BEGIN
    -- 这里可以写触发器的逻辑
END;

SELECT E.Name, D.DepartmentName
FROM Employee E
JOIN Department D ON E.DepartmentID = D.DepartmentID;

SELECT Name, Department
FROM Employee
WHERE Department IN (SELECT DepartmentName FROM Department WHERE Location = 'NY');

SELECT AVG(Salary) AS AverageSalary
FROM Employee;

SELECT Department, AVG(Salary) AS AverageSalary
FROM Employee
GROUP BY Department;