对比显示每条线路的价格和该类型线路的平均价格，分别使用子查询和 exists 获取线路数量

其他 2021-02-26 00:22:35 阅读次数: 0

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需求说明：

对比显示每条线路的价格和该类型线路的平均价格

分别使用子查询和 exists 获取线路数量超过“出境游”线路数的线路类型信息，要求按照线路数升序显示线路类型编号和线路数

实现思路：

需求说明（1）的解决思路

  • 在 from 子句中显示当前线路所属类型的平均价格

需求说明（2）的解决思路

  • 单行子查询：从线路类型表获取线路名为“出境游”的线路类型编号
  • 多行子查询：使用 count( 线路编号 ) 从线路表获取“出境游”的线路数，将从单行子查询中获取的线路类型编号作为比较条件
  • 主查询：在线路表中，依据线路类型编号进行分组，使用 count( 线路编号 ) 计算出不同类型的线路数，并使用 having 子句对分组数据进行限制，将从多行子查询中获取的“出境游”线路数作为限制条件

实现代码：

对比显示每条线路的价格和该类型线路的平均价格

SELECT A.lineTypeID 类型,lineName 线路名,price 价格,该线路类型平均价格 FROM line A,
(SELECT lineTypeID, AVG(price) 该线路类型平均价格 FROM line GROUP BY lineTypeID) B
WHERE A.lineTypeID=B.lineTypeID;

分别使用子查询和 exists 获取线路数量超过“出境游”线路数的线路类型信息，要求按照线路数升序显示线路类型编号和线路数

SELECT lineTypeID 线路类型编号 ,COUNT(lineID) 线路数 FROM line GROUP BY lineTypeID
HAVING COUNT(lineID)>(SELECT COUNT(lineID) FROM line WHERE lineTypeID=
(SELECT lineTypeID FROM lineType WHERE typeName='出境游'));

数据库：

/*
Navicat MySQL Data Transfer

Source Server         : mysql-1
Source Server Version : 50624
Source Host           : localhost:3306
Source Database       : journey

Target Server Type    : MYSQL
Target Server Version : 50624
File Encoding         : 65001

Date: 2019-01-26 11:19:38
*/

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for `customer`
-- ----------------------------
DROP TABLE IF EXISTS `customer`;
CREATE TABLE `customer` (
  `customerID` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(50) NOT NULL,
  `gender` varchar(50) DEFAULT NULL,
  `identityID` varchar(18) DEFAULT NULL,
  `tel` varchar(18) DEFAULT NULL,
  PRIMARY KEY (`customerID`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of customer
-- ----------------------------
INSERT INTO `customer` VALUES ('1', '魏国兰', '女', '420103198309125344', '13923561234');
INSERT INTO `customer` VALUES ('2', '刘亚蒙', '男', '420105197610200916', '13867893421');
INSERT INTO `customer` VALUES ('3', '郝琼琼', '女', '420104198703125881', '15902712563');
INSERT INTO `customer` VALUES ('4', '雷亚波', '男', '420103199806195830', '13686035678');
INSERT INTO `customer` VALUES ('5', '李慧娟', '女', '420106199208113738', '13798235671');

-- ----------------------------
-- Table structure for `line`
-- ----------------------------
DROP TABLE IF EXISTS `line`;
CREATE TABLE `line` (
  `lineID` int(11) NOT NULL AUTO_INCREMENT,
  `lineTypeID` int(11) DEFAULT NULL,
  `lineName` varchar(50) NOT NULL,
  `days` int(11) DEFAULT NULL,
  `price` decimal(10,2) DEFAULT NULL,
  `vehicle` char(10) DEFAULT NULL,
  `hotel` char(10) DEFAULT NULL,
  `hasMeal` char(2) DEFAULT NULL,
  PRIMARY KEY (`lineID`)
) ENGINE=InnoDB AUTO_INCREMENT=22 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of line
-- ----------------------------
INSERT INTO `line` VALUES ('1', '1', '黄陂木兰天池', '1', '159.00', '大巴', '无', '无');
INSERT INTO `line` VALUES ('2', '1', '大别山天堂寨', '2', '429.00', '大巴', '二星级', '无');
INSERT INTO `line` VALUES ('5', '1', '恩施大峡谷', '4', '1089.00', '火车卧铺', '二星级', '无');
INSERT INTO `line` VALUES ('6', '1', '庐山', '2', '729.00', '大巴', '二星级', '含');
INSERT INTO `line` VALUES ('7', '1', '凤凰古城', '3', '959.00', '火车卧铺', '二星级', '含');
INSERT INTO `line` VALUES ('8', '1', '黄山', '3', '1099.00', '动车', '三星级', '含');
INSERT INTO `line` VALUES ('9', '2', '海南岛三亚', '5', '3868.00', '飞机', '三星级', '含');
INSERT INTO `line` VALUES ('10', '2', '青岛蓬莱', '4', '2680.00', '飞机', '三星级', '含');
INSERT INTO `line` VALUES ('12', '2', '桂林', '5', '1920.00', '火车卧铺', '二星级', '无');
INSERT INTO `line` VALUES ('13', '2', '华东五市', '6', '2856.00', '动车', '三星级', '含');
INSERT INTO `line` VALUES ('14', '2', '成都九寨沟', '7', '4500.00', '飞机', '三星级', '含');
INSERT INTO `line` VALUES ('15', '2', '西安', '4', '2180.00', '动车', '三星级', '无');
INSERT INTO `line` VALUES ('16', '3', '欧洲德法意瑞', '13', '12294.91', '飞机', '四星级', '含');
INSERT INTO `line` VALUES ('17', '3', '日本东京富士山', '6', '7119.09', '飞机', '三星级', '含');
INSERT INTO `line` VALUES ('18', '3', '新马泰', '8', '6058.80', '飞机', '三星级', '含');
INSERT INTO `line` VALUES ('19', '3', '美国夏威夷', '6', '11493.90', '飞机', '四星级', '无');
INSERT INTO `line` VALUES ('20', null, '梁子湖游', '1', '168.00', '大巴', '无', '无');
INSERT INTO `line` VALUES ('21', null, '洪湖游', '1', '128.00', '大巴', '无', '无');

-- ----------------------------
-- Table structure for `linetype`
-- ----------------------------
DROP TABLE IF EXISTS `linetype`;
CREATE TABLE `linetype` (
  `lineTypeID` int(11) NOT NULL AUTO_INCREMENT,
  `typeName` varchar(50) DEFAULT NULL,
  PRIMARY KEY (`lineTypeID`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of linetype
-- ----------------------------
INSERT INTO `linetype` VALUES ('1', '国内短线游');
INSERT INTO `linetype` VALUES ('2', '国内长线游');
INSERT INTO `linetype` VALUES ('3', '出境游');

-- ----------------------------
-- Table structure for `oc_detail`
-- ----------------------------
DROP TABLE IF EXISTS `oc_detail`;
CREATE TABLE `oc_detail` (
  `travelCustomerID` int(11) NOT NULL,
  `ordersID` int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of oc_detail
-- ----------------------------
INSERT INTO `oc_detail` VALUES ('1', '1');
INSERT INTO `oc_detail` VALUES ('1', '2');
INSERT INTO `oc_detail` VALUES ('2', '3');
INSERT INTO `oc_detail` VALUES ('2', '5');
INSERT INTO `oc_detail` VALUES ('2', '7');
INSERT INTO `oc_detail` VALUES ('3', '3');
INSERT INTO `oc_detail` VALUES ('3', '4');
INSERT INTO `oc_detail` VALUES ('3', '7');
INSERT INTO `oc_detail` VALUES ('4', '3');
INSERT INTO `oc_detail` VALUES ('4', '5');
INSERT INTO `oc_detail` VALUES ('4', '8');
INSERT INTO `oc_detail` VALUES ('4', '9');
INSERT INTO `oc_detail` VALUES ('5', '1');
INSERT INTO `oc_detail` VALUES ('5', '6');

-- ----------------------------
-- Table structure for `ol_detail`
-- ----------------------------
DROP TABLE IF EXISTS `ol_detail`;
CREATE TABLE `ol_detail` (
  `ordersID` int(11) NOT NULL,
  `lineID` int(11) NOT NULL,
  `travelDate` date DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of ol_detail
-- ----------------------------
INSERT INTO `ol_detail` VALUES ('1', '2', '2018-10-27');
INSERT INTO `ol_detail` VALUES ('2', '5', '2018-01-20');
INSERT INTO `ol_detail` VALUES ('2', '7', '2018-02-01');
INSERT INTO `ol_detail` VALUES ('3', '1', '2018-06-26');
INSERT INTO `ol_detail` VALUES ('3', '6', '2018-07-05');
INSERT INTO `ol_detail` VALUES ('4', '13', '2018-08-29');
INSERT INTO `ol_detail` VALUES ('5', '1', '2018-10-16');
INSERT INTO `ol_detail` VALUES ('5', '14', '2018-10-21');
INSERT INTO `ol_detail` VALUES ('6', '18', '2018-07-10');
INSERT INTO `ol_detail` VALUES ('7', '15', '2018-10-19');
INSERT INTO `ol_detail` VALUES ('8', '19', '2018-11-27');
INSERT INTO `ol_detail` VALUES ('9', '7', '2018-12-28');

-- ----------------------------
-- Table structure for `orders`
-- ----------------------------
DROP TABLE IF EXISTS `orders`;
CREATE TABLE `orders` (
  `ordersID` int(11) NOT NULL AUTO_INCREMENT,
  `customerID` int(11) DEFAULT NULL,
  `ordersDate` date DEFAULT NULL,
  `amount` decimal(8,2) DEFAULT NULL,
  `man_times` int(11) DEFAULT NULL,
  `discount` decimal(8,2) DEFAULT NULL,
  `effectiveAmount` decimal(8,2) DEFAULT NULL,
  PRIMARY KEY (`ordersID`)
) ENGINE=InnoDB AUTO_INCREMENT=10 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of orders
-- ----------------------------
INSERT INTO `orders` VALUES ('1', '1', '2018-10-20', '798.00', '2', '0.98', '782.04');
INSERT INTO `orders` VALUES ('2', '1', '2018-01-15', '1898.00', '2', '0.98', '1860.04');
INSERT INTO `orders` VALUES ('3', '2', '2018-06-18', '2574.00', '6', '0.96', '2471.04');
INSERT INTO `orders` VALUES ('4', '3', '2018-08-21', '2856.00', '1', '1.00', '2856.00');
INSERT INTO `orders` VALUES ('5', '4', '2018-10-10', '7698.00', '4', '0.96', '7390.08');
INSERT INTO `orders` VALUES ('6', '5', '2018-06-23', '6732.00', '1', '1.00', '6732.00');
INSERT INTO `orders` VALUES ('7', '3', '2018-10-11', '4360.00', '2', '0.98', '4272.80');
INSERT INTO `orders` VALUES ('8', '4', '2018-11-21', '12771.00', '1', '1.00', '12771.00');
INSERT INTO `orders` VALUES ('9', '4', '2013-12-20', '899.00', '1', '0.98', '881.02');

-- ----------------------------
-- View structure for `v_customer_orderline_detail`
-- ----------------------------
DROP VIEW IF EXISTS `v_customer_orderline_detail`;
CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`127.0.0.1` SQL SECURITY DEFINER VIEW `v_customer_orderline_detail` AS select `c`.`name` AS `客户名`,`l`.`lineName` AS `线路名`,`l`.`days` AS `行程天数`,`l`.`price` AS `价格` from (((`customer` `c` join `oc_detail` `ocd`) join `ol_detail` `old`) join `line` `l`) where ((`c`.`customerID` = `ocd`.`travelCustomerID`) and (`ocd`.`ordersID` = `old`.`ordersID`) and (`old`.`lineID` = `l`.`lineID`)) ;

-- ----------------------------
-- View structure for `v_customer_orders_detail`
-- ----------------------------
DROP VIEW IF EXISTS `v_customer_orders_detail`;
CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`127.0.0.1` SQL SECURITY DEFINER VIEW `v_customer_orders_detail` AS select `c`.`name` AS `name`,`l`.`lineName` AS `lineName`,`l`.`days` AS `days`,`l`.`price` AS `price` from (((`customer` `c` join `oc_detail` `ocd`) join `ol_detail` `old`) join `line` `l`) where ((`c`.`customerID` = `ocd`.`travelCustomerID`) and (`ocd`.`ordersID` = `old`.`ordersID`) and (`old`.`lineID` = `l`.`lineID`)) ;

-- ----------------------------
-- View structure for `v_nums_line`
-- ----------------------------
DROP VIEW IF EXISTS `v_nums_line`;
CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`127.0.0.1` SQL SECURITY DEFINER VIEW `v_nums_line` AS select `l`.`lineName` AS `线路`,count(`old`.`lineID`) AS `预订数` from (`line` `l` join `ol_detail` `old`) where (`l`.`lineID` = `old`.`lineID`) group by `l`.`lineName` ;

-- ----------------------------
-- Procedure structure for `proc_adjust_price`
-- ----------------------------
DROP PROCEDURE IF EXISTS `proc_adjust_price`;
DELIMITER ;;
CREATE DEFINER=`root`@`127.0.0.1` PROCEDURE `proc_adjust_price`(
		out oldPrice decimal,   -- 原价
		out newPrice decimal,   -- 现价
		out lineName_maxPrice varchar(50) -- 价格最高国内长线游线路名
)
    MODIFIES SQL DATA
begin
		declare lineID_maxPrice int; -- 价格最高国内长线游线路编号
		select max(price) into oldPrice from line where lineTypeID=
			(select lineTypeID from linetype where typeName='国内长线游');
		select lineID, lineName into lineID_maxPrice, lineName_maxPrice from line 
			where price=oldPrice and lineTypeID=(select lineTypeID from linetype where typeName='国内长线游');
		if oldPrice<3000 then
			set newPrice=oldPrice;
		elseif oldPrice>=3000 and oldPrice<4000 then
			set newPrice=oldPrice*0.95;
		elseif oldPrice>=4000 and oldPrice<5000 then
			set newPrice=oldPrice*0.93;
		else
			set newPrice=oldPrice*0.90;
		end if;
		if newPrice<>oldPrice then
			update line set price=newPrice where lineID=lineID_maxPrice;
		end if;
end
;;
DELIMITER ;

-- ----------------------------
-- Procedure structure for `proc_deleteLineType`
-- ----------------------------
DROP PROCEDURE IF EXISTS `proc_deleteLineType`;
DELIMITER ;;
CREATE DEFINER=`root`@`127.0.0.1` PROCEDURE `proc_deleteLineType`(
		_typeName varchar(20) -- 线路类型名称
)
    MODIFIES SQL DATA
begin
		declare state varchar(20);
		declare _lineTypeID int;   -- 线路类型编号
		-- 定义错误处理
		declare continue handler for sqlexception set state='error';
		select lineTypeID into _lineTypeID from LineType where typeName=_typeName;
		-- 开启事务
start transaction;
		-- 将线路中所需要删除的线路类型的编号置为NULL
		update line set lineTypeID=NULL where lineTypeID=_lineTypeID;
		if(state='error') then
			select '线路信息修改失败';
			rollback;
		else
			delete from LineType where typeName=_typeName;
			if(state='error') then
				select '线路类型删除失败';
				rollback;
			else
				select '线路类型删除成功';
				commit;
			end if;
		end if;
end
;;
DELIMITER ;

-- ----------------------------
-- Procedure structure for `proc_LineDetail`
-- ----------------------------
DROP PROCEDURE IF EXISTS `proc_LineDetail`;
DELIMITER ;;
CREATE DEFINER=`root`@`127.0.0.1` PROCEDURE `proc_LineDetail`(
		_lineName varchar(20)
)
    READS SQL DATA
begin
	select lineName 线路名, days 行程天数, price 价格, vehicle 交通工具, hotel 住宿标准 
	from line where lineName=_lineName;
end
;;
DELIMITER ;

-- ----------------------------
-- Procedure structure for `proc_LineNumsRate`
-- ----------------------------
DROP PROCEDURE IF EXISTS `proc_LineNumsRate`;
DELIMITER ;;
CREATE DEFINER=`root`@`127.0.0.1` PROCEDURE `proc_LineNumsRate`(
		_typeName varchar(20), 
		out numsRate decimal(10,3)
)
    READS SQL DATA
begin
		declare totalNum int; -- 定义全部线路数
declare num int;  -- 定义指定类型的线路数
		select count(*) into totalNum from line;
		select count(*) into num from line L, linetype LT where L.lineTypeID=LT.lineTypeID 
and LT.typeName=_typeName;
		-- 生成指定类型的线路数与全部线路数之比，赋给输出参数numsRate
		set numsRate=num*1.0/totalNum;
end
;;
DELIMITER ;

-- ----------------------------
-- Procedure structure for `proc_NumsGivenLineType`
-- ----------------------------
DROP PROCEDURE IF EXISTS `proc_NumsGivenLineType`;
DELIMITER ;;
CREATE DEFINER=`root`@`127.0.0.1` PROCEDURE `proc_NumsGivenLineType`(
		_typeName varchar(20),  
		out count int  -- 输出参数，用于输出指定线路类型的总预订数
)
    READS SQL DATA
begin
		select count(OLD.lineID) into count from ol_detail OLD, line L, lineType LT
		where OLD.lineID=L.lineID and L.lineTypeID=LT.lineTypeID and typeName=_typeName;
end
;;
DELIMITER ;

-- ----------------------------
-- Procedure structure for `proc_PriceModify`
-- ----------------------------
DROP PROCEDURE IF EXISTS `proc_PriceModify`;
DELIMITER ;;
CREATE DEFINER=`root`@`127.0.0.1` PROCEDURE `proc_PriceModify`()
    MODIFIES SQL DATA
begin
		declare _lineID int; 
		declare _days int; -- 线路旅程天数
		declare reduce_money decimal(10,2); -- 减免的住宿费
		declare state varchar(20); -- 错误状态
		declare line_cursor1 cursor for select lineID, days from line where hotel='二星级';
		declare continue handler for 1329 set state='error';
		open line_cursor1;
		traverse_line:while true do
			fetch line_cursor1 into _lineID, _days;			
			if(state='error') then
				leave traverse_line;
			end if;
			set reduce_money=(_days-1)*30;
			update line set price=price-reduce_money where lineID=_lineID;
		end while;
		close line_cursor1;
end
;;
DELIMITER ;

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