描述

Customers 表有字段，顾客名称：cust_name、顾客id：cust_id

cust_id	cust_name
cust10	andy
cust1	ben
cust2	tony
cust22	tom
cust221	an
cust2217	hex

Orders订单信息表，含有字段，订单号：order_num、顾客id：cust_id

order_num	cust_id
a1	cust10
a2	cust1
a3	cust2
a4	cust22
a5	cust221
a7	cust2217

OrderItems表有字段，商品订单号：order_num、商品数量：quantity、商品价格：item_price

order_num	quantity	item_price
a1	1000	10
a2	200	10
a3	10	15
a4	25	50
a5	15	25
a7	7	7

【问题】

除了返回顾客名称和订单号，返回 Customers 表中的顾客名称（cust_name）和Orders 表中的相关订单号（order_num），添加第三列 OrderTotal，其中包含每个订单的总价，并按顾客名称再按订单号对结果进行升序排序。

【示例结果】返回顾客名称 cust_name、订单号order_num、订单总额OrderTotal

cust_name	order_num	OrderTotal
an	a5	375
andy	a1	10000
ben	a2	2000
hex	a7	49
tom	a4	1250
tony	a3	150

【示例解析】

例如顾客名称cust_name为an的顾客的订单a5的订单总额为quantity*item_price = 15 * 25 = 375，最后以cust_name和order_num来进行升序排序。

示例1

输入：

DROP TABLE IF EXISTS `Orders`;
CREATE TABLE IF NOT EXISTS `Orders`(order_num VARCHAR(255) NOT NULL COMMENT '商品订单号',cust_id VARCHAR(255) NOT NULL COMMENT '顾客id'
);
INSERT `Orders` VALUES ('a1','cust10'),('a2','cust1'),('a3','cust2'),('a4','cust22'),('a5','cust221'),('a7','cust2217');DROP TABLE IF EXISTS `Customers`;
CREATE TABLE IF NOT EXISTS `Customers`(cust_id VARCHAR(255) NOT NULL COMMENT '客户id',cust_name VARCHAR(255) NOT NULL COMMENT '客户姓名'
);
INSERT `Customers` VALUES ('cust10','andy'),('cust1','ben'),('cust2','tony'),('cust22','tom'),('cust221','an'),('cust2217','hex');DROP TABLE IF EXISTS `OrderItems`;
CREATE TABLE IF NOT EXISTS `OrderItems`(order_num VARCHAR(255) NOT NULL COMMENT '商品订单号',quantity INT(16) NOT NULL COMMENT '商品数量',item_price INT(16) NOT NULL COMMENT '商品价格'
);
INSERT `OrderItems` VALUES ('a1',1000,10),('a2',200,10),('a3',10,15),('a4',25,50),('a5',15,25),('a7',7,7);

复制输出：

an|a5|375
andy|a1|10000
ben|a2|2000
hex|a7|49
tom|a4|1250
tony|a3|150

复制

《SQL必知必会（第5版）》独家授权

答案

select t1.cust_name,t2.order_num,sum(t3.quantity*t3.item_price) as orderTotal
from Customers t1,Orders t2,OrderItems t3
where t1.cust_id=t2.cust_id
and t2.order_num=t3.order_num
group by t1.cust_name,t2.order_num
order by t1.cust_name,t2.order_num