SQL Server命令大全

SQL Server 中包含了大量的命令用于数据库的管理、查询和操作。以下是一些主要命令分类及其简要示例：

1. 数据库管理

• 创建数据库

CREATE DATABASE MyDatabase;

• 删除数据库

DROP DATABASE MyDatabase;

• 选择/切换当前数据库

USE MyDatabase;

2. 表操作

• 创建表

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

• 插入数据

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

• 更新数据

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

• 删除数据

DELETE FROM Employees
WHERE EmployeeID = 1;

• 修改表结构

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

3. 查询数据

• 基本查询

SELECT * FROM Employees;

• 条件查询

SELECT * FROM Employees WHERE DepartmentID = 2;

• 排序查询

SELECT * FROM Employees ORDER BY HireDate DESC;

• 聚合函数查询

SELECT COUNT(*) FROM Employees;

• 分组查询

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

4. 连接查询

• 内连接

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

5. 存储过程与函数

• 创建存储过程

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

• 调用存储过程

EXEC GetEmployeesByDepartment 2;

• 创建用户定义函数

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

• 使用函数

SELECT dbo.GetTotalEmployees(2) AS TotalEmpInDept2;

6. 视图

• 创建视图

CREATE VIEW EmployeeNames AS
SELECT FirstName, LastName FROM Employees;

• 查询视图

SELECT * FROM EmployeeNames;

7. 索引

• 创建索引

CREATE INDEX IX_Employees_DepartmentID ON Employees (DepartmentID);

• 删除索引

DROP INDEX IX_Employees_DepartmentID ON Employees;

8. 其他常用命令

• 事务控制

BEGIN TRANSACTION;
-- 执行一系列操作...
COMMIT TRANSACTION;

• 备份还原

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

9. 用户与权限管理

• 创建登录账户

CREATE LOGIN NewUser WITH PASSWORD = 'StrongPassword!';

• 创建数据库用户并映射到登录名

CREATE USER UserForDB FOR LOGIN NewUser;
ALTER ROLE db_datareader ADD MEMBER UserForDB; -- 给予读权限
ALTER ROLE db_datawriter ADD MEMBER UserForDB; -- 给予写权限

• 撤销用户对数据库的访问

DROP USER UserForDB;

• 授予、拒绝或撤销权限

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

10. 数据备份与恢复

• 完整数据库备份

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

• 差异备份

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

• 事务日志备份

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

• 还原数据库

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

11. 系统函数与信息查询

• 查询当前数据库版本

SELECT @@VERSION;

• 查询表结构信息

sp_help 'Employees';

• 获取当前时间

SELECT GETDATE() AS CurrentDateTime;

12. 其他高级特性

• 窗口函数

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

• CTE（公用表表达式）

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

13. 分区表

• 创建分区函数

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

• 创建分区方案

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

• 创建分区表

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

14. 高级查询操作

• 联合查询（UNION、UNION ALL）

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

• INTERSECT和EXCEPT操作

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;

15. 复制与同步

• 使用SQL Server Replication进行数据复制
  这涉及到一系列复杂的配置步骤，包括发布设置、订阅设置、代理设置等。

16. 异步处理与作业调度

• 创建SQL Server Agent作业

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

-- 添加作业步骤
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

-- 启用作业调度
EXEC dbo.sp_add_schedule
    @schedule_name = N'DailyAtMidnight',
    @freq_type = 4, -- 每日
    @freq_interval = 1, -- 每天运行一次
    @active_start_time = 000000; -- 在午夜开始

-- 将作业与调度关联
EXEC sp_attach_schedule
    @job_name = N'MyBackupJob', 
    @schedule_name = N'DailyAtMidnight';
GO

17. 查询执行计划

• 查看查询执行计划

-- 在查询语句前添加EXPLAIN 或者 SET SHOWPLAN_ALL ON
SET SHOWPLAN_ALL ON;
SELECT * FROM Employees WHERE DepartmentID = 1;
SET SHOWPLAN_ALL OFF;

-- 或使用图形化方式查看
-- 在SQL Server Management Studio中，运行查询后右键选择"包括实际执行计划"
SELECT * FROM Employees WHERE DepartmentID = 1;

18. 引用外部数据

• OPENROWSET函数读取文件

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

• 链接服务器

-- 创建链接服务器
EXEC sp_addlinkedserver @server = N'MyLinkedServer', @srvproduct=N'OtherDB', @provider=N'SQLNCLI', @datasrc=N'ServerName\InstanceName';

-- 使用链接服务器查询数据
SELECT * 
FROM MyLinkedServer.RemoteDB.dbo.Employees;

19. 动态SQL

• 构建并执行动态SQL语句

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

20. 自增序列与标识符

• 创建带有自增列的表

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

21. 数据类型转换

• 显式转换

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

22. CASE表达式和IIF函数

• CASE表达式

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

• IIF函数（SQL Server 2012及以上版本）

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

23. 数据库快照

• 创建数据库快照

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

• 从快照恢复数据

RESTORE DATABASE MyDatabase FROM DATABASE_SNAPSHOT = 'MyDatabase_snapshot';

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