新建一个数据库
- 创建一张表suppliers,并插入数据
CREATE TABLE suppliers
(
s_id int NOT NULL AUTO_INCREMENT,
s_name char(50) NOT NULL,
s_city char(50) NULL,
s_zip char(10) NULL,
s_call CHAR(50) NOT NULL,
PRIMARY KEY (s_id)
) ;
为了演示的需要，我们需要插入数据
INSERT INTO suppliers(s_id, s_name,s_city, s_zip, s_call)
VALUES(101,'FastFruit Inc.','Tianjin','300000','48075'),
(102,'LT Supplies','Chongqing','400000','44333'),
(103,'ACME','Shanghai','200000','90046'),
(104,'FNK Inc.','Zhongshan','528437','11111'),
(105,'Good Set','Taiyuang','030000', '22222'),
(106,'Just Eat Ours','Beijing','010', '45678'),
(107,'DK Inc.','Zhengzhou','450000', '33332');
- 查询之前，先来看一下两个表的结构
1.内连接
- 在fruits表和suppliers表之间使用内连接查询
SELECT suppliers.s_id, s_name,f_name, f_price FROM fruits ,suppliers WHERE fruits.s_id = suppliers.s_id;
- 使用 inner join 语法进行内连接查询
SELECT suppliers.s_id, s_name,f_name, f_price
FROM fruits
INNER JOIN suppliers ON fruits.s_id = suppliers.s_id;
再创建一张表orders
CREATE TABLE orders
(
o_num int NOT NULL AUTO_INCREMENT,
o_date datetime NOT NULL,
c_id int NOT NULL,
PRIMARY KEY (o_num)
) ;
向表插入数据
2.左连接
SELECT customers.c_id, orders.o_num
FROM customers LEFT OUTER JOIN orders
ON customers.c_id = orders.c_id;
3.右连接
SELECT customers.c_id, orders.o_num
from customers RIGHT OUTER JOIN orders
ON customers.c_id = orders.c_id;
4.复合条件连接查询
SELECT customers.c_id, orders.o_num
FROM customers INNER JOIN orders
ON customers.c_id = orders.c_id AND customers.c_id = 10001;
SELECT suppliers.s_id, s_name,f_name, f_price
FROM fruits INNER JOIN suppliers
ON fruits.s_id = suppliers.s_id
ORDER BY fruits.s_id;
- 在fruits表和suppliers表之间使用内连接查询，查询之前，查看两个表的结构
SELECT suppliers.s_id, s_name,f_name, f_price
FROM fruits ,suppliers
WHERE fruits.s_id = suppliers.s_id;
- 在fruits表和suppliers表之间使用INNER JOIN语法进行内连接查询
SELECT suppliers.s_id, s_name,f_name, f_price
FROM fruits INNER JOIN suppliers
ON fruits.s_id = suppliers.s_id;
- 查询供应f_id='a1’的水果供应商提供的其他水果种类
SELECT f1.f_id, f1.f_name
FROM fruits AS f1, fruits AS f2
WHERE f1.s_id = f2.s_id AND f2.f_id = 'a1';
- 在customers表和orders表中，查询所有客户，包括没有订单的客户，SQL语法如下
SELECT customers.c_id, orders.o_num
FROM customers LEFT OUTER JOIN orders
ON customers.c_id = orders.c_id;
- 在customers表和orders表中，查询所有订单，包括没有客户的订单
SELECT customers.c_id, orders.o_num
from customers RIGHT OUTER JOIN orders
ON customers.c_id = orders.c_id;
- 在customers表和orders表中，使用INNER JOIN语法查询customers表中ID为10001、的客户的订单信息
SELECT customers.c_id, orders.o_num
FROM customers INNER JOIN orders
ON customers.c_id = orders.c_id AND customers.c_id = 10001;
- 在fruits表和suppliers表之间使用INNER JOIN语法进行内连接查询，并对查询结果排序
SELECT suppliers.s_id, s_name,f_name, f_price
FROM fruits INNER JOIN suppliers
ON fruits.s_id = suppliers.s_id
ORDER BY fruits.s_id;
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