CREATE DATABASE MyDatabase;

DROP DATABASE MyDatabase;

USE MyDatabase;

CREATE TABLE Employees (
    EmployeeID int PRIMARY KEY,
    FirstName nvarchar(50),
    LastName nvarchar(50),
    HireDate datetime
);

INSERT INTO Employees (EmployeeID, FirstName, LastName, HireDate)
VALUES (1, 'John', 'Doe', '2023-01-01');

UPDATE Employees
SET FirstName = 'Jane'
WHERE EmployeeID = 1;

DELETE FROM Employees
WHERE EmployeeID = 1;

ALTER TABLE Employees
ADD DepartmentID int FOREIGN KEY REFERENCES Departments(DepartmentID);

SELECT * FROM Employees;

SELECT * FROM Employees WHERE DepartmentID = 2;

SELECT * FROM Employees ORDER BY HireDate DESC;

SELECT COUNT(*) FROM Employees;

SELECT DepartmentID, COUNT(*) AS CountOfEmployees
FROM Employees
GROUP BY DepartmentID;

SELECT E.FirstName, D.DepartmentName 
FROM Employees E
INNER JOIN Departments D ON E.DepartmentID = D.DepartmentID;

CREATE PROCEDURE GetEmployeesByDepartment @deptId INT
AS
BEGIN
    SELECT * FROM Employees WHERE DepartmentID = @deptId;
END

EXEC GetEmployeesByDepartment 2;

CREATE FUNCTION dbo.GetTotalEmployees(@deptId INT) RETURNS INT
AS
BEGIN
    RETURN (SELECT COUNT(*) FROM Employees WHERE DepartmentID = @deptId);
END

SELECT dbo.GetTotalEmployees(2) AS TotalEmpInDept2;

CREATE VIEW EmployeeNames AS
SELECT FirstName, LastName FROM Employees;

SELECT * FROM EmployeeNames;

CREATE INDEX IX_Employees_DepartmentID ON Employees (DepartmentID);

DROP INDEX IX_Employees_DepartmentID ON Employees;

BEGIN TRANSACTION;
-- 執(zhí)行一系列操作...
COMMIT TRANSACTION;

BACKUP DATABASE MyDatabase TO DISK = 'C:\backup\MyDatabase.bak';
RESTORE DATABASE MyDatabase FROM DISK = 'C:\backup\MyDatabase.bak';

CREATE LOGIN NewUser WITH PASSWORD = 'StrongPassword!';

CREATE USER UserForDB FOR LOGIN NewUser;
ALTER ROLE db_datareader ADD MEMBER UserForDB; -- 給予讀權(quán)限
ALTER ROLE db_datawriter ADD MEMBER UserForDB; -- 給予寫權(quán)限

DROP USER UserForDB;

GRANT SELECT ON Employees TO UserForDB;
DENY UPDATE ON Employees TO UserForDB;
REVOKE DELETE ON Employees FROM UserForDB;

BACKUP DATABASE MyDatabase
TO DISK = 'C:\Backup\MyDatabase.bak'
WITH FORMAT, MEDIANAME = 'MyDatabase_Full', NAME = 'Full Backup';

BACKUP DATABASE MyDatabase
TO DISK = 'C:\Backup\MyDatabase_diff.bak'
WITH DIFFERENTIAL, FORMAT, MEDIANAME = 'MyDatabase_Diff', NAME = 'Differential Backup';

BACKUP LOG MyDatabase
TO DISK = 'C:\Backup\MyDatabase_log.trn'
WITH NOFORMAT, NOINIT, NAME = N'MyDatabase_LogBackup', SKIP, NOREWIND, NOUNLOAD, STATS = 10;

RESTORE DATABASE MyDatabase
FROM DISK = 'C:\Backup\MyDatabase.bak'
WITH FILE = 1, NOUNLOAD, REPLACE, STATS = 5;

SELECT @@VERSION;

sp_help 'Employees';

SELECT GETDATE() AS CurrentDateTime;

SELECT 
    EmployeeID, 
    FirstName, 
    Salary,
    AVG(Salary) OVER (PARTITION BY DepartmentID) AS AvgSalaryInDept
FROM Employees;

WITH EmpSalaries AS (
    SELECT EmployeeID, Salary
    FROM Employees
)
SELECT * FROM EmpSalaries WHERE Salary > (SELECT AVG(Salary) FROM EmpSalaries);

CREATE PARTITION FUNCTION pf_EmployeesRange (int)
AS RANGE RIGHT FOR VALUES 
(2000, 2005, 2010, 2015);

CREATE PARTITION SCHEME ps_Employees 
AS PARTITION pf_EmployeesRange 
TO (
    [PrimaryFileGroup], 
    [SecondaryFileGroup1],
    [SecondaryFileGroup2],
    [SecondaryFileGroup3]
);

CREATE TABLE PartitionedEmployees (
    EmployeeID int PRIMARY KEY,
    HireDate int NOT NULL
) ON ps_Employees(HireDate);

SELECT FirstName, LastName FROM Employees WHERE DepartmentID = 1
UNION ALL
SELECT FirstName, LastName FROM Employees WHERE DepartmentID = 2;

SELECT EmployeeID FROM Employees WHERE DepartmentID = 1
INTERSECT
SELECT EmployeeID FROM Employees WHERE DepartmentID = 2;

SELECT EmployeeID FROM Employees WHERE DepartmentID = 1
EXCEPT
SELECT EmployeeID FROM Employees WHERE DepartmentID = 2;

USE msdb;
GO
EXEC sp_add_job @job_name=N'MyBackupJob', 
                @enabled=1, 
                @description='Daily backup job';
GO

-- 添加作業(yè)步驟
EXEC sp_add_jobstep @job_name=N'MyBackupJob', 
                   @step_name=N'Backup Database',
                   @subsystem=N'TSQL', 
                   @command=N'BACKUP DATABASE MyDatabase TO DISK = ''C:\Backup\MyDatabase.bak'';',
                   @retry_attempts=5, 
                   @retry_interval=5;
GO

-- 啟用作業(yè)調(diào)度
EXEC dbo.sp_add_schedule
    @schedule_name = N'DailyAtMidnight',
    @freq_type = 4, -- 每日
    @freq_interval = 1, -- 每天運(yùn)行一次
    @active_start_time = 000000; -- 在午夜開始

-- 將作業(yè)與調(diào)度關(guān)聯(lián)
EXEC sp_attach_schedule
    @job_name = N'MyBackupJob', 
    @schedule_name = N'DailyAtMidnight';
GO

-- 在查詢語句前添加EXPLAIN 或者 SET SHOWPLAN_ALL ON
SET SHOWPLAN_ALL ON;
SELECT * FROM Employees WHERE DepartmentID = 1;
SET SHOWPLAN_ALL OFF;

-- 或使用圖形化方式查看
-- 在SQL Server Management Studio中，運(yùn)行查詢后右鍵選擇"包括實(shí)際執(zhí)行計(jì)劃"
SELECT * FROM Employees WHERE DepartmentID = 1;

SELECT *
FROM OPENROWSET('Microsoft.ACE.OLEDB.12.0', 'Text;Database=C:\Data;HDR=YES;FMT=Delimited', 'SELECT * FROM [Employees.txt]');

-- 創(chuàng)建鏈接服務(wù)器
EXEC sp_addlinkedserver @server = N'MyLinkedServer', @srvproduct=N'OtherDB', @provider=N'SQLNCLI', @datasrc=N'ServerName\InstanceName';

-- 使用鏈接服務(wù)器查詢數(shù)據(jù)
SELECT * 
FROM MyLinkedServer.RemoteDB.dbo.Employees;

DECLARE @DepartmentID INT = 1;
DECLARE @SQL NVARCHAR(MAX) = N'SELECT * FROM Employees WHERE DepartmentID = ' + CAST(@DepartmentID AS NVARCHAR(10));
EXEC sp_executesql @SQL;

CREATE TABLE Orders (
    OrderID INT IDENTITY(1,1),
    CustomerID INT,
    OrderDate DATE,
    PRIMARY KEY (OrderID)
);

SELECT CAST('1234' AS INT), CONVERT(INT, '1234');

SELECT EmployeeID, FirstName, LastName,
    CASE WHEN Salary > 50000 THEN 'High'
         WHEN Salary > 30000 THEN 'Medium'
         ELSE 'Low'
    END AS SalaryLevel
FROM Employees;

SELECT EmployeeID, FirstName, LastName,
    IIF(Salary > 50000, 'High', IIF(Salary > 30000, 'Medium', 'Low')) AS SalaryLevel
FROM Employees;

CREATE DATABASE MyDatabase_snapshot ON 
    (NAME = MyDatabase, FILENAME = 'C:\Snapshots\MyDatabase_snapshot.ss')
AS SNAPSHOT OF MyDatabase;

RESTORE DATABASE MyDatabase FROM DATABASE_SNAPSHOT = 'MyDatabase_snapshot';