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SQL必知必会学习笔记

时间：2021-07-01 10:21:17 帮助过：7人阅读

--------------------------------------------------------- -- 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); 创建表技术分享图片

-------------------------------------------------------------
-- 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

2.5 select

SELECT       要返回的列或表达式    是
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
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

SELECT prod_id, prod_price, prod_name
FROM Products
ORDER BY 3, 2;  --先排第3列,在其基础上排第2列

SELECT prod_id, prod_price, prod_name
FROM Products
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

<>	!=	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

SELECT cust_name FROM CUSTOMERS
WHERE cust_email IS NULL; --显示其列cust_email为空的 cust_name

5.1逻辑操作符

and 满足二个子句

or 满足其中一个

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

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

ABS()	绝对值	PI()	圆周率	SQRT()	平方根	EXP()	指数值
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