總結MySQL的高級查詢(二)

一.單詞部分

①exist存在②temp臨時的③district區(qū)域

④content內容⑤temporary暫時的

二.預習部分

1.表連接都可以用子查詢替換嗎

是的

2.檢測某列是否存在某個范圍可以在子查詢中使用什么關鍵字

EXISTS

3.哪些sql語句可以嵌套子查詢

較復雜的數(shù)據(jù)查詢語句 需要多個表的數(shù)據(jù)的時候

子查詢可以出現(xiàn)在任何表達式出現(xiàn)的位置

三.練習部分

1.查詢S2學員考試成績信息

#上機1
SELECT `studentNo`,`subjectNo`,`studentResult`,`exameDate` FROM `result`
WHERE EXISTS(SELECT `studentNo` FROM `student` WHERE gradeId=2)
AND studentNo IN(SELECT `studentNo` FROM `student` WHERE gradeId=2)

2.制作學生成績單

#上機2
SELECT `studentName` AS 姓名,`gradeName` AS 課程所屬年級,`subjectName` AS 課程名稱,`exameDate` AS 考試日期 FROM (
SELECT `studentName`,`gradeName`,`subjectName`,`exameDate` FROM `grade` AS gr,`result` AS re,`student` AS stu,`subject` AS sub
WHERE gr.`gradeID`=stu.`gradeID` AND re.`studentNo`=stu.`studentNo`
AND re.`subjectNo`=sub.`subjectNo`
) AS tempt;

3.統(tǒng)計Logic Java課程最近一次考試學生應到人數(shù)，實到人數(shù)和缺考人數(shù)

提取結果到臨時表

#上機3
#select subjectNo from `subject` where `subjectName`='Logic Java';

#select max(`exameDate`) from result inner join `subject` on `result`.`subjectNo`=`subject`.`subjectNo`
#where `subjectName`='Logic Java';

#select `gradeID` from `subject` where `subjectName`='Logic Java';
#應到人數(shù)
SELECT COUNT(*) AS 應到人數(shù) FROM student
WHERE `gradeID`=(SELECT `gradeID` FROM `subject` WHERE `subjectName`='Logic Java');
#實到人數(shù)
SELECT COUNT(*) AS 實到人數(shù) FROM result
WHERE `subjectNo`=(SELECT subjectNo FROM `subject` WHERE `subjectName`='Logic Java')
AND exameDate=(SELECT MAX(`exameDate`) FROM result INNER JOIN `subject` ON `result`.`subjectNo`=`subject`.`subjectNo`
WHERE `subjectName`='Logic Java');
#缺考人數(shù)
SELECT((SELECT COUNT(*) FROM student
WHERE `gradeID`=(SELECT `gradeID` FROM `subject` WHERE `subjectName`='Logic Java'))-
(SELECT COUNT(*) FROM result
WHERE `subjectNo`=(SELECT subjectNo FROM `subject` WHERE `subjectName`='Logic Java')
AND exameDate=(SELECT MAX(`exameDate`) FROM result INNER JOIN `subject` ON `result`.`subjectNo`=`subject`.`subjectNo`
WHERE `subjectName`='Logic Java'))) AS 缺考人數(shù);

/*select studentName,student.studentNo,studentResult
from student,result
where student.`studentNo`=result.`studentNo`*/
#添加到表
DROP TABLE IF EXISTS tempResult;
CREATE TABLE tempResult(
SELECT studentName,student.studentNo,studentResult
FROM student,result
WHERE student.`studentNo`=result.`studentNo`
)

4.分頁查詢顯示出租房屋信息

#上機4
DROP DATABASE IF EXISTS `house`;

CREATE DATABASE house;
USE house;
#客戶信息表
DROP TABLE IF EXISTS `sys_user`;

CREATE TABLE `sys_user`(

`uid` INT(4) NOT NULL COMMENT '客戶編號' AUTO_INCREMENT PRIMARY KEY,

`uName` VARCHAR(50) COMMENT '客戶姓名',

`uPassWord` VARCHAR(50) COMMENT '客戶密碼'
);

#區(qū)縣信息表
DROP TABLE IF EXISTS `hos_district`;

CREATE TABLE `hos_district`(

`did` INT(4) NOT NULL COMMENT '區(qū)縣編號' AUTO_INCREMENT PRIMARY KEY,

`dName` VARCHAR(50) NOT NULL COMMENT '區(qū)縣名稱'
);

#街道信息表這里有一個外鍵
DROP TABLE IF EXISTS `hos_street`;

CREATE TABLE `hos_street`(

`sid` INT(4) NOT NULL COMMENT '街道編號' AUTO_INCREMENT PRIMARY KEY,

`sName` VARCHAR(50) COMMENT '街道名稱',

`sDid` INT(4) NOT NULL COMMENT '區(qū)縣編號'
);

#房屋類型表
DROP TABLE IF EXISTS `hos_type`;

CREATE TABLE `hos_type`(

`hTid` INT(4) NOT NULL COMMENT '房屋類型編號' AUTO_INCREMENT PRIMARY KEY,

`htName` VARCHAR(50) NOT NULL COMMENT '房屋類型名稱'
);

#出租房屋信息表
DROP TABLE IF EXISTS `hos_house`;

CREATE TABLE `hos_house`(

`hMid` INT(4) NOT NULL COMMENT '出租房屋編號' AUTO_INCREMENT PRIMARY KEY,

`uid` INT(4) NOT NULL COMMENT '客戶編號',

`sid` INT(4) NOT NULL COMMENT '區(qū)縣編號',

`hTid` INT(4) NOT NULL COMMENT '房屋類型編號',

`price` DECIMAL NOT NULL COMMENT '每月租金',

`topic` VARCHAR(50) NOT NULL COMMENT '標題',

`contents` VARCHAR(255) NOT NULL COMMENT '描述',

`hTime` TIMESTAMP NOT NULL COMMENT '發(fā)布時間' DEFAULT NOW(),

`copy` VARCHAR(255) NOT NULL COMMENT '備注'
);

#各個約束信息

#街道信息的區(qū)縣編號外鍵id
ALTER TABLE `hos_street` ADD CONSTRAINT fk_stree_distr
FOREIGN KEY (`sDid`) REFERENCES `hos_district` (`did`);

#出租屋信息和各個表的聯(lián)系
ALTER TABLE `hos_house` ADD CONSTRAINT fk_house_user
FOREIGN KEY (`uid`) REFERENCES `sys_user` (`uid`);

ALTER TABLE `hos_house` ADD CONSTRAINT fk_house_street
FOREIGN KEY (`sid`) REFERENCES `hos_street` (`sid`);

ALTER TABLE `hos_house` ADD CONSTRAINT fk_house_type
FOREIGN KEY (`hTid`) REFERENCES `hos_type` (`hTid`);

#默認約束
ALTER TABLE `hos_house` ALTER COLUMN `price` SET DEFAULT 0;

#ALTER TABLE `hos_house` ALTER COLUMN `hTime` SET DEFAULT now();

#添加信息

#用戶表
INSERT INTO `house`.`sys_user` (`uName`, `uPassWord`) VALUES ('小漠', '123'),
('百順', '123'),
('練基', '123'),
('冬梅', '123');

#區(qū)縣信息表
INSERT INTO `house`.`hos_district` (`dName`) VALUES ('海淀區(qū)'),
('東城區(qū)'),
('南城區(qū)'),
('西城區(qū)'),
('開發(fā)區(qū)');

#街道信息表
INSERT INTO `house`.`hos_street` (`sName`) VALUES ('萬泉');
INSERT INTO `house`.`hos_street` (`sName`, `sDid`) VALUES ('萬泉', '1');
INSERT INTO `house`.`hos_street` (`sName`, `sDid`) VALUES ('中關', '3');
INSERT INTO `house`.`hos_street` (`sName`, `sDid`) VALUES ('萬嘉', '4');
INSERT INTO `house`.`hos_street` (`sName`, `sDid`) VALUES ('海風', '5');

#房屋類型表
INSERT INTO `house`.`hos_type` (`htName`) VALUES ('一室一廳');
INSERT INTO `house`.`hos_type` (`htName`) VALUES ('兩室一廳');
INSERT INTO `house`.`hos_type` (`htName`) VALUES ('三室一廳');
INSERT INTO `house`.`hos_type` (`htName`) VALUES ('兩室一衛(wèi)');
INSERT INTO `house`.`hos_type` (`htName`) VALUES ('一室一衛(wèi)');

#出租房屋信息表
INSERT INTO `house`.`hos_house` (`uid`, `sid`, `hTid`, `price`, `topic`, `contents`, `hTime`, `copy`)
VALUES ('1', '1', '1', '530', '觀景房', '陽臺觀賞大海', '2017-7-7', '需要的速度買');
INSERT INTO `house`.`hos_house` (`uid`, `sid`, `hTid`, `price`, `topic`, `contents`, `hTime`, `copy`)
VALUES ('2', '2', '2', '430', '大床房', '舒服睡覺', '2017-6-9', '好舒服');
INSERT INTO `house`.`hos_house` (`uid`, `sid`, `hTid`, `price`, `topic`, `contents`, `hTime`, `copy`)
VALUES ('3', '3', '3', '480', '雙人房', '嘿嘿嘿', '2016-9-9', '懂不懂');
INSERT INTO `house`.`hos_house` (`uid`, `sid`, `hTid`, `price`, `topic`, `contents`, `hTime`, `copy`)
VALUES ('4', '4', '4', '360', '單人房', '旅行必選', '2015-8-8', '等你來選');

#上機4
CREATE TEMPORARY TABLE temp_house
(SELECT * FROM `hos_house` LIMIT 2,2);
SELECT * FROM temp_house;

5.查詢指定客戶發(fā)布的出租屋信息

#上機5
#select `uid` from `sys_user` where uName='大漠';
SELECT `dName`,`sName`,hou.`hTid`,`price`,`topic`,`contents`,`hTime`,`copy`
FROM `hos_house` AS hou,`hos_district` AS dist,`hos_street` AS str,`sys_user` AS us,`hos_type` AS ty
WHERE hou.`uid`=us.`uid` AND hou.`hTid`=ty.`hTid` AND hou.`sid`=str.`sid` AND str.`sDid`=dist.`did`
AND hou.`uid`=(SELECT `uid` FROM `sys_user` WHERE uName='大漠');

6.按區(qū)縣制作房屋出租清單

#上機6
/*select sid from `hos_house` group by sid having count(sid)>1;
select `sDid` from `hos_street`
where sid=(SELECT sid FROM `hos_house` GROUP BY sid HAVING COUNT(sid)>1);
select `dName` from `hos_district` where `did`=(SELECT `sDid` FROM `hos_street`
WHERE sid=(SELECT sid FROM `hos_house` GROUP BY sid HAVING COUNT(sid)>1));*/
SELECT `htName`,`uName`,`dName`,`sName`
FROM `hos_house` AS hou,`hos_district` AS dist,`hos_street` AS str,`sys_user` AS us,`hos_type` AS ty
WHERE hou.`uid`=us.`uid` AND hou.`hTid`=ty.`hTid` AND hou.`sid`=str.`sid` AND str.`sDid`=dist.`did`
AND hou.sid=(SELECT sid FROM `hos_house` GROUP BY sid HAVING COUNT(sid)>1);

7.按區(qū)縣制作房屋出租清單

#上機7 QUARTER(NOW())獲取季度
/*FROM `hos_house` AS hou,`hos_district` AS dist,`hos_street` AS str,`sys_user` AS us,`hos_type` AS ty
GROUP BY hou.`hMid`
WHERE hou.`uid`=us.`uid` AND hou.`hTid`=ty.`hTid` AND hou.`sid`=str.`sid` AND str.`sDid`=dist.`did`*/

SELECT QQ AS '季度',dist.`dName` AS '區(qū)縣',str.`sName` AS '街道',
ty.`htName` AS '戶型',CNT AS '房屋數(shù)量'
FROM
(
SELECT QUARTER(`hTime`) AS QQ,`sid` AS SI,`hTid` AS HT,COUNT(*) CNT
FROM `hos_house` AS hou
WHERE QUARTER(`hTime`)
GROUP BY QUARTER(`hTime`),`sid`,`hTid`
) AS temp,`hos_district` dist,`hos_street` AS str,`hos_type` AS ty,`hos_house` AS hou
WHERE hou.`hTid`=ty.`hTid` AND hou.`sid`=str.`sid` AND str.`sDid`=dist.`did`

UNION

SELECT QUARTER(`hTime`),`hos_district`.`dName`,' 小計 ',' ',COUNT(*) AS '房屋數(shù)量'
FROM `hos_house`
INNER JOIN `hos_street` ON(hos_house.`sid`=hos_street.`sid`)
INNER JOIN hos_district ON(hos_street.`sDid`=hos_district.`did`)
WHERE QUARTER(`hTime`)
GROUP BY QUARTER(`hTime`),hos_district.`dName`
UNION

SELECT QUARTER(`hTime`),' 合計 ',' ',' ',COUNT(*) AS '房屋數(shù)量'
FROM hos_house
WHERE QUARTER(`hTime`)
GROUP BY QUARTER(`hTime`)
ORDER BY 1,2,3,4

五.總結

UNION有點陌生其它沒什么。。。。。

歡迎提問，歡迎指錯，歡迎討論學習信息 有需要的私聊 發(fā)布評論即可 都能回復的

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