SQL必知必会学习笔记

2.5  select

SELECT 要返回的 列或表达式
FROM 从中检索数据的表 仅在从表选择数据时使用
where 行级过滤 否
group by 分组说明 仅在按组计算聚集时使用
having 组级过滤 否
order by 输出排序顺序 否

SELECT DISTINCT vend_id, prod_price --会列出二列数据不相同每行不同的数据</span>
FROM Products

3.1排序

SELECT prod_id, prod_price, prod_name
FROM Products
ORDER BY prod_price, prod_name;   --排序 先排prod_price顺序,然后在其基础上排prod_name
--ORDER BY 3, 2;  --先排第3列,在其基础上排第2列
--ORDER BY  prod_name DESC,prod_price DESC; --DESC是反转,先排前面的,再排后面的

4.1where

• 排序ORDER BY应该在where之后
• where的字段不是一定要在select里出现的
• ''单引号用来限定字符串,与数值
• 区分大小写查询时应在字段后面加入collate Chinese_PRC_CS_AS如where str collate Chinese_PRC_CS_AS ='i'

符号		说明
<>	!=	不等于 注:Access支持<>不支持!=
!		不(非) 不可单用,用于组合
>=		大于等于
BETWEEN		在指定的两个值之间
IS NULL		为NULL值 (NULL表示无值的意思)

SELECT prod_name, prod_price 
FROM Products
WHERE prod_price BETWEEN 5 AND 10; --在二者之间
--WHERE prod_name IS NULL; --显示列prod_name为空的数据

5.1逻辑操作符

• and（并且） or（或者）

SELECT prod_name, prod_price FROM Products
WHERE vend_id = 'DLL01' OR vend_id = 'BRS01' AND prod_price >= 10;--SQL（像多数语言一样）在处理OR操作符前，优先处理AND操作符
--等价于vend_id = 'DLL01' OR (vend_id = 'BRS01' AND prod_price >= 10)

所以如果想先OR 应该在or二个条件加括号

• IN操作符 指定条件范围 (注in比or操作更快)

SELECT prod_name, prod_price FROM Products
WHERE vend_id IN ( 'DLL01', 'BRS01' ) ORDER BY prod_name;--显示包含了'DLL01', 'BRS01'的

• NOT操作符 排除

SELECT prod_name FROM Products
WHERE NOT vend_id = 'DLL01' ORDER BY prod_name;--除去'DLL01' 的所有都显示出来

6.1 LIKE操作符

• 多个通配符%

任何字符出现任意次数 (注 Access需要使用*)  不匹配null

SELECT prod_id, prod_name FROM Products 
WHERE prod_name LIKE 'Fish%';  --开头为Fish的

• 单个通配符_ 匹配单个字符

(注 Access需要使用?)不匹配null  语法和%一样

• []通配符 匹配一个字符,内容为方括号内的

SELECT cust_contact FROM Customers
WHERE cust_contact LIKE '[JM]%' --匹配J或M开头的cust_contact

7.2计算字段

• 拼接字段

SELECT vend_name + ' (' + vend_country + ')' FROM Vendors ORDER BY vend_name;--拼接vend_name与end_country字段

• RTRIM()删除右边的空格
• LTRIM()删除左边的空格
• trim()删除左右二边的空格

SELECT RTRIM(vend_name) + ' (' + RTRIM(vend_country) + ')' FROM Vendors ORDER BY vend_name;--删除右边的空格再合并

• AS 显示别名

SELECT vend_name  AS vend_title FROM Vendors --用vend_title别名显示结果

• 执行算术运算

SELECT prod_id, quantity, item_price, 
quantity*item_price AS expanded_price --把查询到的quantity与item_price字段的结果相乘用expanded_price显示 
FROM OrderItems  WHERE order_num = 20008;

8.1函数

-字符处理函数

函数	说明	函数	说明
LEFT(字段,2)	返回字符串左边的2个字符	RIGHT(字段,2)	返回字符串右边的2个字符
LOWER(字段)	将字符串转换为小写	UPPER(字段)	将字符串转换为大写
LTRIM(字段)	去掉字符串左边的空格	RTRIM(字段)	去掉字符串右边的空格
Soundex(字段)	返回字符串的SOUNDEX值主要用于英语读法相似的(略过)	length(字段)	返回字符串的长度

• 日期处理函数

SELECT order_num,order_date FROM Orders
WHERE DATEPART(yy, order_date) = 2012; --表示字段order_date的年份为2012年的
--DATEPART(M, order_date)如果是M则表示月份是5月,d为日,H为时,mm为分,ss为秒

• 数值处理函数

函数	说明	函数	说明	函数	说明
ABS()	绝对值	PI()	圆周率	SQRT()	平方根
COS()	角度余弦	SIN()	角度正弦	TAN()	角度正切

• 聚集函数

函数	说明	函数	说明	函数	说明
AVG()	平均值	COUNT()	计数(共几行)	MAX()	最大值
MIN()	最小值	SUM()	总计(和运算)

SELECT COUNT(*) AS num_items,
       MIN(prod_price) AS price_min,
       MAX(prod_price) AS price_max,
       AVG(prod_price) AS price_avg
FROM Products;

10.2分组与过滤

SELECT order_num, COUNT(*) AS items
FROM OrderItems
GROUP BY order_num     --这里按order_num分组 
HAVING COUNT(*) >= 3 --这里给分组过滤,显示分组大于3的 
ORDER BY items, order_num;   --排序方式,可以理解为对结果的排序处理

11 使用子查询

个人理解 先得到子句应放在where后面，如果是先得父句则在from前

• 先得到子句的结果再去查询 (注意嵌套子查询只能单列(多列将返回错误))

SELECT cust_name, cust_contact
FROM Customers
WHERE cust_id IN (
    SELECT cust_id FROM Order WHERE order_num IN (
        SELECT order_num FROM OrderItems
        WHERE prod_id = 'RGAN01'
        )
    );

• 先得到父句的结果再去查询子句

SELECT cust_name,cust_state,(
   SELECT COUNT(*)
        FROM Orders 
        WHERE Orders.cust_id = Customers.cust_id
    ) AS orders --这里的子句用结果中的Customers.cust_id为条件去查询(只能返回一个) 
    FROM Customers 
ORDER BY cust_name;

12 联结

多表联结,则使用and

SELECT cust_name, cust_contact 
FROM Customers, Orders, OrderItems
WHERE Customers.cust_id = Orders.cust_id AND OrderItems.order_num = Orders.order_num AND prod_id = 'RGAN01';
--只显示指定条件的内容

自联结

SELECT c1.cust_id, c1.cust_name, c1.cust_contact
FROM Customers AS c1, Customers AS c2
WHERE c1.cust_name = c2.cust_name   --找c1表内与c2结果列名cust_name一样的的记录 
AND c2.cust_contact = 'Jim Jones'; --先找到jim Jones那一行,得到c2表的一行

外连接

• 左联接 LEFT OUTER JOIN

SELECT Customers.cust_id, Orders.order_num
FROM Customers 
LEFT OUTER JOIN Orders ---以左边的表为基础显示结果 
ON Customers.cust_id = Orders.cust_id;

• 右联接 RIGHT OUTER JOIN

SELECT Customers.cust_id, Orders.order_num
FROM Customers 
RIGHT OUTER JOIN Orders --右边表为基础显示结果 
ON Orders.cust_id = Customers.cust_id;

• 全联接 FULL OUTER JOIN

SELECT Customers.cust_id, Orders.order_num
FROM Orders 
FULL OUTER JOIN Customers --显示比二个表为基础的结果 
ON Orders.cust_id = Customers.cust_id;

• 左连接并分组计算

SELECT Customers.cust_id,
       COUNT(Orders.order_num) AS num_ord
FROM Customers LEFT OUTER JOIN Orders
 ON Customers.cust_id = Orders.cust_id
GROUP BY Customers.cust_id;

• 组合查询UNION

(二个结果同一行会被自动取消) (合并结果,二个查询结果的字段要一致,类型能隐式转换)

SELECT cust_name, cust_contact, cust_email
FROM Customers
WHERE cust_state IN ('IL','IN','MI')
UNION -- 这里改成UNION ALL则显示二个查询的集合,不会自动取消同一行 SELECT cust_name, cust_contact, cust_email
FROM Customers
WHERE cust_name = 'Fun4All';

15 数据插入

• 插入检索出来的数据

INSERT INTO Customers
(cust_id,cust_contact,cust_email,cust_name,cust_address,cust_city,cust_state,cust_zip,cust_country)
SELECT --从CustNew查询的结果插入到Customers表中,插入时主要为列的顺序,非字段名 
cust_id,cust_contact,cust_email,cust_name,cust_address,cust_city,cust_state,cust_zip,cust_country
FROM CustNew;

• 复制新表

SELECT * --所有列,如果只是部分,应指定列名 
INTO CustCopy  --新的表名 
FROM Customers;

16 更新数据

UPDATE Customers
SET cust_contact = 'Sam Roberts',
    cust_email = 'sam@toyland.com', --也可以直接设置为null 
    cust_email = NULL 
WHERE cust_id = '1000000006';  --更新时一定要注意过滤,不然所有行都会更新掉

• 删除数据

注!删除前最好使用select检索结果,看where是否有错

DELETE FROM Customers
WHERE cust_id = '1000000006';

17创建表

CREATE TABLE OrderItems
(
    order_num INTEGER NOT NULL PRIMARY KEY, --不能为空值,不允许NULL值 PRIMARY KEY主键 
    order_item INTEGER NULL, --表示可以为空值 
    prod_id varchar(10) NOT NULL, --char为固定长度(会被填未满10位为空格)varchar(10)是可变长度,
    quantity INTEGER NOT NULL DEFAULT 1, --默认值为1 item_price DECIMAL(8,2) --省略NOT NULL时,默认可以为空l
);

完整写法

GO
--判断非空的写法WHERE 字段 IS NULL
SET ANSI_NULLS ON
GO
--标识符可以由双引号分隔,文字必须由单引号分隔
SET QUOTED_IDENTIFIER ON
GO
--允许空值的Char(n)和binary(n)列填充到列长
SET ANSI_PADDING ON
GO
CREATE TABLE [dbo].[Pc_ADAccount]
(
[F_Id] [varchar](50) NOT NULL,
[F_Account] [varchar](50) NULL,
[F_AccountName] [varchar](50) NULL,
[F_EmpId] [varchar](50) NULL,
[F_PublicAccount] [bit] NULL,
[F_RestrictLogOnPC] [varchar](50) NULL,
--为多个键定义约束(PK_SYS_ADAccount为) asc升序NONCLUSTERED非聚集索引
CONSTRAINT [PK_Pc_ADAccount] PRIMARY KEY NONCLUSTERED 
(
    [F_Id] ASC
)WITH (PAD_INDEX  = OFF, 
STATISTICS_NORECOMPUTE  = OFF, 
IGNORE_DUP_KEY = OFF, 
ALLOW_ROW_LOCKS  = ON, 
ALLOW_PAGE_LOCKS  = ON
) ON [PRIMARY]
) ON [PRIMARY]

GETDATE()系统时间

修改表

慎用下面命令

• 添加 修改 移除列

ALTER TABLE Vendors
ADD vend_phone CHAR(20) --添加一列
--ALTER COLUMN vend_phone NVARCHAR(Max) --修改列类型
--DROP COLUMN vend_phone; --移除一列

• 修改列的字段名

exec sp_rename '表名.原列名','新列名','column';--SQL Server用户使用sp_rename存储过程重命名表

• 删除表

DROP TABLE CustCopy;--可以使用关系规则防止意外删除

18视图

CREATE VIEW CustomerEMailList AS --创建视图,创建一个cust_email不为空的表,查询时和表格一样操作 
SELECT cust_id, cust_name, cust_email
FROM Customers
WHERE cust_email IS NOT NULL;

19存储过程

• 执行存储过程

execute AddNewProduct( 'JTS01', 'Stuffed Eiffel Tower',6.49,'this is test' );--执行存储过程,其参数有多个

• 创建存储过程

create procedure NewOrder 
@cust_id CHAR(10) --参数
AS
SET NOCOUNT OFF -- 显示受影响的行数 
declare @order_num integer  -- 声明变量 
select @order_num=MAX(order_num) from Orders -- 获取当前最高订单号 
select @order_num=@order_num+1 -- 确定下一个订单号 
insert into Orders(order_num, order_date, cust_id) values(@order_num, GETDATE(), @cust_id) 
return @order_num;-- 返回的订单号

--下面是测试显示 
declare @str int
exec @str = NewOrder artre 
select @str

20管理事务处理

相关知识点

注意:书本的实例测试时,部分有问题,这里请查询网上相关资料为准

• 事务管理

BEGIN TRAN --开始事务
INSERT INTO Customers(cust_id, cust_name)VALUES('1000000017', 'Toys Emporium'); 
INSERT INTO Customers(cust_id, cust_name)VALUES('1000000010', 'Toys Emporium');
if @@ERROR <> 0 Rollback tran;  --ERROR为SQL函数,出错时ERROR不为零,意在上面的操作中有错误时回滚事务 
COMMIT TRAN --这是提交事务,可以理解为,之前BEGIN TRAN之后的一系列操作还没保存!在时才会保存到源数据里 
select * from Customers

• 事务保存点

begin Tran;  --这是TRANSACTION的缩写 在begin Tran这后总有一个ROLLBACK Tran回滚事务或commit tran执行事务, 
save tran test_1; --保存点test_1 
DELETE FROM CustNew where cust_id = '1000000002';
save tran test_2;  --保存点test_2 
DELETE FROM CustNew where cust_id = '1000000003';
ROLLBACK Tran test_1; --回滚至保存点test_2 ,
--commit tran;  --提交事务,事务的结束,如果没设置自动结束,事务会占用资源,无法查询 
select * from CustNew;

21游标

游标很少用于ASP等 参考资料

DECLARE CustCursor CURSOR ----声明时未指定"local"或"global"关键字,系统默认游标是"global(全局)"的. 
FOR SELECT * FROM Customers WHERE cust_email IS NULL OPEN CustCursor  --在open时,执行查询,存储检索出的数据以供浏览和滚动. 
FETCH NEXT FROM CustCursor --读取游标数据,其中的NEXT为下一行记录,详见附2,这里可以执行 单语句运行 
CLOSE CustCursor; --关闭游标 
Deallocate CustCursor; --释放游标
/*
附1:标准游标:Declare MyCursor Cursor For Select * From Master_Goods
    只读游标:Declare MyCusror Cursor For Select * From Master_Goods For Read Only
    可更新游标:Declare MyCusror Cursor For Select * From Master_Goods For UpDate
附2:Next表示返回结果集中当前行的下一行记录，如果第一次读取则返回第一行。默认的读取选项为Next

Prior表示返回结果集中当前行的前一行记录，如果第一次读取则没有行返回，并且把游标置于第一行之前。

First表示返回结果集中的第一行，并且将其作为当前行。

Last表示返回结果集中的最后一行，并且将其作为当前行。

Absolute　n　如果n为正数，则返回从游标头开始的第n行，并且返回行变成新的当前行。如果n为负，则返回从游标末尾开始的第n行，并且返回行为新的当前行，如果n为0，则返回当前行。

Relative　n　如果n为正数，则返回从当前行开始的第n行，如果n为负,则返回从当前行之前的第n行，如果为0，则返回当前行。
 */

22约束

CREATE TABLE Vendors (
  vend_id         CHAR(10)       NOT NULL PRIMARY KEY, --Primary key设置为主键
  vend_name       CHAR(50)       NOT NULL,
  )
ALTER TABLE Vendors  --修改列 
ADD CONSTRAINT PRIMARY KEY (vend_id);--改为主键 使用的是Constraintd 强迫

• 外键

CREATE TABLE Orders
(
    order_num     INTEGER     NOT NULL PRIMARY KEY,
    order_date    DATETIME    NOT NULL,
    cust_id       CHAR(10)    NOT NULL REFERENCES Customers(cust_id) --定义外键为Customers的cust_id字段
);

• 检查约束

CREATE TABLE OrderItems
(
    order_num     INTEGER     NOT NULL,
    order_item    INTEGER     NOT NULL,
    prod_id       CHAR(10)    NOT NULL,
    quantity      INTEGER     NOT NULL CHECK (quantity > 0), --约束其列值必须大于0
    item_price    MONEY       NOT NULL
);
ADD CONSTRAINT CHECK (gender LIKE '[MF]') --检查列中只包含M或F

• 索引

CREATE INDEX prod_name_ind --建立索引 
ON PRODUCTS (prod_name); --建立索引的表下的列

• 触发器

CREATE TRIGGER customer_state --建立索引 
ON Customers --表名Customers
FOR INSERT, UPDATE --插入与修改操作
AS UPDATE Customers
SET cust_state = Upper(cust_state) --cust_state列 
WHERE Customers.cust_id = inserted.cust_id; --插入的数据表等于源数据的cust_id列

---

以下为示例用数据表

创建表格

-----------------------------------------------------------
-- Sams Teach Yourself SQL in 10 Minutes
-- http://forta.com/books/0672336073/
-- Example table creation scripts for Microsoft SQL Server.
-----------------------------------------------------------
-------------------------
-- Create Customers table
-------------------------
CREATE TABLE Customers
(
cust_id      char(10)  NOT NULL ,
cust_name    char(50)  NOT NULL ,
cust_address char(50)  NULL ,
cust_city    char(50)  NULL ,
cust_state   char(5)   NULL ,
cust_zip     char(10)  NULL ,
cust_country char(50)  NULL ,
cust_contact char(50)  NULL ,
cust_email   char(255) NULL
);
--------------------------
-- Create OrderItems table
--------------------------
CREATE TABLE OrderItems
(
order_num  int          NOT NULL ,
order_item int          NOT NULL ,
prod_id    char(10)     NOT NULL ,
quantity   int          NOT NULL ,
item_price decimal(8,2) NOT NULL
);
----------------------
-- Create Orders table
----------------------
CREATE TABLE Orders
(
order_num  int      NOT NULL ,
order_date datetime NOT NULL ,
cust_id    char(10) NOT NULL
);
------------------------
-- Create Products table
------------------------
CREATE TABLE Products
(
prod_id    char(10)      NOT NULL ,
vend_id    char(10)      NOT NULL ,
prod_name  char(255)     NOT NULL ,
prod_price decimal(8,2)  NOT NULL ,
prod_desc  varchar(1000) NULL
);
-----------------------
-- Create Vendors table
-----------------------
CREATE TABLE Vendors
(
vend_id      char(10) NOT NULL ,
vend_name    char(50) NOT NULL ,
vend_address char(50) NULL ,
vend_city    char(50) NULL ,
vend_state   char(5)  NULL ,
vend_zip     char(10) NULL ,
vend_country char(50) NULL
);
----------------------
-- Define primary keys
----------------------
ALTER TABLE Customers WITH NOCHECK ADD CONSTRAINT PK_Customers PRIMARY KEY CLUSTERED (cust_id);
ALTER TABLE OrderItems WITH NOCHECK ADD CONSTRAINT PK_OrderItems PRIMARY KEY CLUSTERED (order_num, order_item);
ALTER TABLE Orders WITH NOCHECK ADD CONSTRAINT PK_Orders PRIMARY KEY CLUSTERED (order_num);
ALTER TABLE Products WITH NOCHECK ADD CONSTRAINT PK_Products PRIMARY KEY CLUSTERED (prod_id);
ALTER TABLE Vendors WITH NOCHECK ADD CONSTRAINT PK_Vendors PRIMARY KEY CLUSTERED (vend_id);
----------------------
-- Define foreign keys
----------------------
ALTER TABLE OrderItems ADD
CONSTRAINT FK_OrderItems_Orders FOREIGN KEY (order_num) REFERENCES Orders (order_num),
CONSTRAINT FK_OrderItems_Products FOREIGN KEY (prod_id) REFERENCES Products (prod_id);
ALTER TABLE Orders ADD
CONSTRAINT FK_Orders_Customers FOREIGN KEY (cust_id) REFERENCES Customers (cust_id);
ALTER TABLE Products ADD
CONSTRAINT FK_Products_Vendors FOREIGN KEY (vend_id) REFERENCES Vendors (vend_id);

插入数据

-------------------------------------------------------------
-- Sams Teach Yourself SQL in 10 Minutes
-- http://forta.com/books/0672336073/
-- Example table population scripts for Microsoft SQL Server.
-------------------------------------------------------------
---------------------------
-- Populate Customers table
---------------------------
INSERT INTO Customers(cust_id, cust_name, cust_address, cust_city, cust_state, cust_zip, cust_country, cust_contact, cust_email)
VALUES('1000000001', 'Village Toys', '200 Maple Lane', 'Detroit', 'MI', '44444', 'USA', 'John Smith', 'sales@villagetoys.com');
INSERT INTO Customers(cust_id, cust_name, cust_address, cust_city, cust_state, cust_zip, cust_country, cust_contact)
VALUES('1000000002', 'Kids Place', '333 South Lake Drive', 'Columbus', 'OH', '43333', 'USA', 'Michelle Green');
INSERT INTO Customers(cust_id, cust_name, cust_address, cust_city, cust_state, cust_zip, cust_country, cust_contact, cust_email)
VALUES('1000000003', 'Fun4All', '1 Sunny Place', 'Muncie', 'IN', '42222', 'USA', 'Jim Jones', 'jjones@fun4all.com');
INSERT INTO Customers(cust_id, cust_name, cust_address, cust_city, cust_state, cust_zip, cust_country, cust_contact, cust_email)
VALUES('1000000004', 'Fun4All', '829 Riverside Drive', 'Phoenix', 'AZ', '88888', 'USA', 'Denise L. Stephens', 'dstephens@fun4all.com');
INSERT INTO Customers(cust_id, cust_name, cust_address, cust_city, cust_state, cust_zip, cust_country, cust_contact)
VALUES('1000000005', 'The Toy Store', '4545 53rd Street', 'Chicago', 'IL', '54545', 'USA', 'Kim Howard');
-------------------------
-- Populate Vendors table
-------------------------
INSERT INTO Vendors(vend_id, vend_name, vend_address, vend_city, vend_state, vend_zip, vend_country)
VALUES('BRS01','Bears R Us','123 Main Street','Bear Town','MI','44444', 'USA');
INSERT INTO Vendors(vend_id, vend_name, vend_address, vend_city, vend_state, vend_zip, vend_country)
VALUES('BRE02','Bear Emporium','500 Park Street','Anytown','OH','44333', 'USA');
INSERT INTO Vendors(vend_id, vend_name, vend_address, vend_city, vend_state, vend_zip, vend_country)
VALUES('DLL01','Doll House Inc.','555 High Street','Dollsville','CA','99999', 'USA');
INSERT INTO Vendors(vend_id, vend_name, vend_address, vend_city, vend_state, vend_zip, vend_country)
VALUES('FRB01','Furball Inc.','1000 5th Avenue','New York','NY','11111', 'USA');
INSERT INTO Vendors(vend_id, vend_name, vend_address, vend_city, vend_state, vend_zip, vend_country)
VALUES('FNG01','Fun and Games','42 Galaxy Road','London', NULL,'N16 6PS', 'England');
INSERT INTO Vendors(vend_id, vend_name, vend_address, vend_city, vend_state, vend_zip, vend_country)
VALUES('JTS01','Jouets et ours','1 Rue Amusement','Paris', NULL,'45678', 'France');
--------------------------
-- Populate Products table
--------------------------
INSERT INTO Products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('BR01', 'BRS01', '8 inch teddy bear', 5.99, '8 inch teddy bear, comes with cap and jacket');
INSERT INTO Products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('BR02', 'BRS01', '12 inch teddy bear', 8.99, '12 inch teddy bear, comes with cap and jacket');
INSERT INTO Products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('BR03', 'BRS01', '18 inch teddy bear', 11.99, '18 inch teddy bear, comes with cap and jacket');
INSERT INTO Products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('BNBG01', 'DLL01', 'Fish bean bag toy', 3.49, 'Fish bean bag toy, complete with bean bag worms with which to feed it');
INSERT INTO Products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('BNBG02', 'DLL01', 'Bird bean bag toy', 3.49, 'Bird bean bag toy, eggs are not included');
INSERT INTO Products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('BNBG03', 'DLL01', 'Rabbit bean bag toy', 3.49, 'Rabbit bean bag toy, comes with bean bag carrots');
INSERT INTO Products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('RGAN01', 'DLL01', 'Raggedy Ann', 4.99, '18 inch Raggedy Ann doll');
INSERT INTO Products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('RYL01', 'FNG01', 'King doll', 9.49, '12 inch king doll with royal garments and crown');
INSERT INTO Products(prod_id, vend_id, prod_name, prod_price, prod_desc)
VALUES('RYL02', 'FNG01', 'Queen doll', 9.49, '12 inch queen doll with royal garments and crown');
------------------------
-- Populate Orders table
------------------------
INSERT INTO Orders(order_num, order_date, cust_id)
VALUES(20005, '2012-05-01', '1000000001');
INSERT INTO Orders(order_num, order_date, cust_id)
VALUES(20006, '2012-01-12', '1000000003');
INSERT INTO Orders(order_num, order_date, cust_id)
VALUES(20007, '2012-01-30', '1000000004');
INSERT INTO Orders(order_num, order_date, cust_id)
VALUES(20008, '2012-02-03', '1000000005');
INSERT INTO Orders(order_num, order_date, cust_id)
VALUES(20009, '2012-02-08', '1000000001');
----------------------------
-- Populate OrderItems table
----------------------------
INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20005, 1, 'BR01', 100, 5.49);
INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20005, 2, 'BR03', 100, 10.99);
INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20006, 1, 'BR01', 20, 5.99);
INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20006, 2, 'BR02', 10, 8.99);
INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20006, 3, 'BR03', 10, 11.99);
INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20007, 1, 'BR03', 50, 11.49);
INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20007, 2, 'BNBG01', 100, 2.99);
INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20007, 3, 'BNBG02', 100, 2.99);
INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20007, 4, 'BNBG03', 100, 2.99);
INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20007, 5, 'RGAN01', 50, 4.49);
INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20008, 1, 'RGAN01', 5, 4.99);
INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20008, 2, 'BR03', 5, 11.99);
INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20008, 3, 'BNBG01', 10, 3.49);
INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20008, 4, 'BNBG02', 10, 3.49);
INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20008, 5, 'BNBG03', 10, 3.49);
INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20009, 1, 'BNBG01', 250, 2.49);
INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20009, 2, 'BNBG02', 250, 2.49);
INSERT INTO OrderItems(order_num, order_item, prod_id, quantity, item_price)
VALUES(20009, 3, 'BNBG03', 250, 2.49);

插入数据

查询死锁

SELECT t1.resource_type AS [锁类型], DB_NAME(resource_database_id) AS [数据库名],
t1.resource_associated_entity_id AS [阻塞资源对象],
t1.resource_description as [资源描述信息], t1.request_mode AS [请求的锁], 
t1.request_session_id AS [等待会话], t2.wait_duration_ms AS [等待时间],       
(SELECT [text] FROM sys.dm_exec_requests AS r WITH (NOLOCK)                      
	CROSS APPLY sys.dm_exec_sql_text(r.[sql_handle]) 
    WHERE r.session_id = t1.request_session_id
) AS [等待会话执行的批SQL],
(SELECT SUBSTRING(qt.[text],r.statement_start_offset/2, 
		(CASE WHEN r.statement_end_offset = -1 
		THEN LEN(CONVERT(nvarchar(max), qt.[text])) * 2 
		ELSE r.statement_end_offset END )/2) 
	FROM sys.dm_exec_requests AS r WITH (NOLOCK)
	CROSS APPLY sys.dm_exec_sql_text(r.[sql_handle]) AS qt
	WHERE r.session_id = t1.request_session_id
) AS [等待会话执行的SQL],                    
t2.blocking_session_id AS [阻塞会话],                                        
(SELECT [text] FROM sys.sysprocesses AS p                                       
	CROSS APPLY sys.dm_exec_sql_text(p.[sql_handle]) 
	WHERE p.spid = t2.blocking_session_id
) AS [阻塞会话执行的批SQL]
FROM sys.dm_tran_locks AS t1 WITH (NOLOCK)
INNER JOIN sys.dm_os_waiting_tasks AS t2 WITH (NOLOCK)
ON t1.lock_owner_address = t2.resource_address OPTION (RECOMPILE);

删除阻塞的会话 kell

计算指定字段后更新到指定字段

update Table_1 set c3 = c1 * c2

触发 同步数据表到另一个数据库内

CREATE TRIGGER sync_trigger 
ON Table_1
AFTER insert
AS 
BEGIN
	INSERT INTO ZKTecoDB.dbo.Table_1(D1,D2) select C1,C2 from inserted
END;

触发 更新时同步到另一个表

ALTER TRIGGER [dbo].[sync_Empinfo_update_trigger] 
ON [dbo].[Empinfo]
for UPDATE 
as
BEGIN 
    declare @姓名 varchar(50);
    declare @工号 varchar(50);
    select @姓名=name,@工号=Badgenumber from inserted //inserted为修改后的一虚拟表，插入新增时的记录在这里 还有另外一个删除的虚拟表deleted
	UPDATE ZKTecoDB.dbo.Empinfo SET name = @姓名 where Badgenumber = @工号
END;
GO