返回顾客名称和相关订单号以及每个订单的总价_牛客题霸

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);

输出

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