Mysql学习---SQL测试题之表结构

创建表结果和数据准备[直接执行即可]

 /*
 Navicat MySQL Data Transfer

 Source Server         : ftl1012
 Source Server Version : 50617
 Source Host           : localhost:3306
 Source Database       : test_python

 Target Server Type    : MYSQL
 Target Server Version : 50617
 File Encoding         : 65001

 Date: 2017-12-30 13:12:57
 */

 SET FOREIGN_KEY_CHECKS=0;

 -- ----------------------------
 -- Table structure for class
 -- ----------------------------
 DROP TABLE IF EXISTS `class`;
 CREATE TABLE `class` (
   `cid` int(11) NOT NULL AUTO_INCREMENT,
   `caption` varchar(32) NOT NULL,
   PRIMARY KEY (`cid`)
 ) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;

 -- ----------------------------
 -- Records of class
 -- ----------------------------
 INSERT INTO `class` VALUES ('', '三年二班');
 INSERT INTO `class` VALUES ('', '三年三班');
 INSERT INTO `class` VALUES ('', '一年二班');
 INSERT INTO `class` VALUES ('', '二年九班');

 -- ----------------------------
 -- Table structure for course
 -- ----------------------------
 DROP TABLE IF EXISTS `course`;
 CREATE TABLE `course` (
   `cid` int(11) NOT NULL AUTO_INCREMENT,
   `cname` varchar(32) NOT NULL,
   `teacher_id` int(11) NOT NULL,
   PRIMARY KEY (`cid`),
   KEY `fk_course_teacher` (`teacher_id`),
   CONSTRAINT `fk_course_teacher` FOREIGN KEY (`teacher_id`) REFERENCES `teacher` (`tid`)
 ) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;

 -- ----------------------------
 -- Records of course
 -- ----------------------------
 INSERT INTO `course` VALUES ('', '生物', '');
 INSERT INTO `course` VALUES ('', '物理', '');
 INSERT INTO `course` VALUES ('', '体育', '');
 INSERT INTO `course` VALUES ('', '美术', '');

 -- ----------------------------
 -- Table structure for score
 -- ----------------------------
 DROP TABLE IF EXISTS `score`;
 CREATE TABLE `score` (
   `sid` int(11) NOT NULL AUTO_INCREMENT,
   `student_id` int(11) NOT NULL,
   `course_id` int(11) NOT NULL,
   `num` int(11) NOT NULL,
   PRIMARY KEY (`sid`),
   KEY `fk_score_student` (`student_id`),
   KEY `fk_score_course` (`course_id`),
   CONSTRAINT `fk_score_course` FOREIGN KEY (`course_id`) REFERENCES `course` (`cid`),
   CONSTRAINT `fk_score_student` FOREIGN KEY (`student_id`) REFERENCES `student` (`sid`)
 ) ENGINE=InnoDB AUTO_INCREMENT=53 DEFAULT CHARSET=utf8;

 -- ----------------------------
 -- Records of score
 -- ----------------------------
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');
 INSERT INTO `score` VALUES ('', '', '', '');

 -- ----------------------------
 -- Table structure for student
 -- ----------------------------
 DROP TABLE IF EXISTS `student`;
 CREATE TABLE `student` (
   `sid` int(11) NOT NULL AUTO_INCREMENT,
   `gender` char(1) NOT NULL,
   `class_id` int(11) NOT NULL,
   `sname` varchar(32) NOT NULL,
   PRIMARY KEY (`sid`),
   KEY `fk_class` (`class_id`),
   CONSTRAINT `fk_class` FOREIGN KEY (`class_id`) REFERENCES `class` (`cid`)
 ) ENGINE=InnoDB AUTO_INCREMENT=17 DEFAULT CHARSET=utf8;

 -- ----------------------------
 -- Records of student
 -- ----------------------------
 INSERT INTO `student` VALUES ('', '男', '', '理解');
 INSERT INTO `student` VALUES ('', '女', '', '钢蛋');
 INSERT INTO `student` VALUES ('', '男', '', '张三');
 INSERT INTO `student` VALUES ('', '男', '', '张一');
 INSERT INTO `student` VALUES ('', '女', '', '张二');
 INSERT INTO `student` VALUES ('', '男', '', '张四');
 INSERT INTO `student` VALUES ('', '女', '', '铁锤');
 INSERT INTO `student` VALUES ('', '男', '', '李三');
 INSERT INTO `student` VALUES ('', '男', '', '李一');
 INSERT INTO `student` VALUES ('', '女', '', '李二');
 INSERT INTO `student` VALUES ('', '男', '', '李四');
 INSERT INTO `student` VALUES ('', '女', '', '如花');
 INSERT INTO `student` VALUES ('', '男', '', '刘三');
 INSERT INTO `student` VALUES ('', '男', '', '刘一');
 INSERT INTO `student` VALUES ('', '女', '', '刘二');
 INSERT INTO `student` VALUES ('', '男', '', '刘四');

 -- ----------------------------
 -- Table structure for teacher
 -- ----------------------------
 DROP TABLE IF EXISTS `teacher`;
 CREATE TABLE `teacher` (
   `tid` int(11) NOT NULL AUTO_INCREMENT,
   `tname` varchar(32) NOT NULL,
   PRIMARY KEY (`tid`)
 ) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;

 -- ----------------------------
 -- Records of teacher
 -- ----------------------------
 INSERT INTO `teacher` VALUES ('', '张磊老师');
 INSERT INTO `teacher` VALUES ('', '李平老师');
 INSERT INTO `teacher` VALUES ('', '刘海燕老师');
 INSERT INTO `teacher` VALUES ('', '朱云海老师');
 INSERT INTO `teacher` VALUES ('', '李杰老师');

经验： join, 临时表的学习[in 的使用，右边只能输出一个]

-- 查询平均成绩大于60分的同学的学号和平均成绩,按照平均成绩降序排序 操作score张表关联student查姓名

方案一[FTL]：
select * from (select student_id, avg(num) from score group by student_id having avg(num) > 60) as T left join student on student.sid = T.student_id;
方案二：
select score.student_id, student.sname, avg(num),max(num),min(num) from score LEFT JOIN student on student.sid = score.student_id
GROUP BY score.student_id having avg(num) > 60 order by avg(num) desc;

-- 查询所有同学的学号、姓名、选课数、总成绩；

SELECT  a.sid, a.sname,
SUM(s.num) as zongchengji, count(s.course_id) as xuankeshu from score s
LEFT JOIN student a on a.sid = s.student_id  GROUP BY s.student_id

-- 查询姓“李”的老师的个数；

方案一[FTL]：select count(tname) from teacher where tname like '李%';
方案二：select count(1) from teacher where tname like '李%';

-- 查询没学过“李平”老师课的同学的学号、姓名；

方案一[FTL]：局限性：不能查其他表中的内容
   -- 没学过  ==> not int ==> sid not in 成绩表
   -- 利用成绩表查找课程信息 ==>关联老师的信息
   -- 李平老师  ==> where tname like '李平'
select student.sid, student.sname from student where sid not in
(
   select student_id from score LEFT JOIN
    course on score.course_id = course.cid
   LEFT JOIN teacher on teacher.tid = course.teacher_id
  where tname like '李平%'
);

方案二：
思路：
    先查到“李平老师”老师教的所有课ID
    获取选过课的所有学生ID
    学生表中筛选
select * from student where sid not in (
    select DISTINCT student_id from score where score.course_id in (
        select cid from course left join teacher on course.teacher_id = teacher.tid where tname = '李平老师'
    )
)

-- 查询学过“001”并且也学过编号“002”课程的同学的学号、姓名；

方案一[FTL]：
   -- 选出课程为1或者2的课 ==> 关联student表查询
SELECT sid,sname from student where sid in
(select DISTINCT student_id from score where score.course_id in
(select cid from course where cid in (1,2)))

方案二：
SELECT sid, sname from
(SELECT student_id, count(student_id) FROM
(SELECT student_id, course_id FROM score WHERE course_id = 1 OR course_id = 2) AS B
GROUP BY student_id HAVING count(student_id) > 1
) as C LEFT JOIN student on student.sid = C.student_id;

方案三：
select student_id,sname from
 (select student_id,course_id from score where course_id = 1 or course_id = 2) as B left join student on B.student_id = student.sid group by student_id HAVING count(student_id) > 1;

-- 查询没有学全所有课的同学的学号、姓名；

-- 查询没有学全所有课的同学的学号、姓名；
   -- 所有课  ==> count(1) from course
   -- 同学的学号、姓名 ==> sid, sname from student
   -- 没有学全所有课   ==> count(course_id)
方案二:
SELECT student.sid, sname from student LEFT JOIN score on score.student_id = student.sid
group by student_id HAVING count(course_id) = (select count(1) from course)

-- 查询学过“李平老师“所教的所有课的同学的学号、姓名；

-- 查询学过“李平老师“所教的所有课的同学的学号、姓名；
-- 找到李平老师教过的课程ID
方案一[FTL]:
SELECT sid, sname FROM student where sid in (SELECT student_id FROM score WHERE course_id IN (SELECT cid FROM course LEFT JOIN teacher ON teacher_id = tid WHERE teacher.tname LIKE '%李平%' ))

方案二:
select sid, sname from (select student_id from score where course_id in (select cid from course left join teacher on course.teacher_id = teacher.tid  where teacher.tname='李平老师') group by student_id)
as B left JOIN student on student.sid = B.student_id

-- 查询所有课程成绩小于60分的同学的学号、姓名；

-- 查询所有课程成绩小于60分的同学的学号、姓名；
方案一[FTL]:
select * from (
select student_id, num from score LEFT JOIN student on student.sid = score.student_id  where num < 60 ORDER BY num asc ) as B LEFT JOIN student on B.student_id = student.sid

-- 查询至少有一门课与学号为“001”的同学所学相同的同学的学号和姓名

-- 查询至少有一门课与学号为“001”的同学所学相同的同学的学号和姓名
方案一[FTL_有错误，未解决]
select student.sid, sname from
(SELECT * from score where course_id in (
	select course_id from score where student_id = 1
)) as B LEFT JOIN student on B.sid = student.sid
方案二：
   思路：
        获取 001 同学选择的所有课程
        获取课程在其中的所有人以及所有课程
        根据学生筛选，获取所有学生信息
        再与学生表连接，获取姓名
select student_id, sname, count(course_id) from score
LEFT JOIN student on student.sid = score.student_id where student_id != 1 and course_id in (
select course_id from score where course_id = 1) GROUP BY student_id

-- 查询至少学过学号为“001”同学所有课数目相同的其他同学学号和姓名

-- 查询至少学过学号为“001”同学所有课数目相同的其他同学学号和姓名
  -- 001 所学习的课程
  -- 其他人的课 >= 001里面的课
方案一[FTL]：
select sid, sname from
(select student_id, course_id from score where course_id in
(select course_id from score where student_id = 1) group by student_id
HAVING count(1) = (select count(1) from score WHERE student_id = 1) ) as B
LEFT JOIN student on student.sid = B.student_id GROUP BY student_id

-- 查询和“002”号的同学学习的课程完全相同的其他同学学号和姓名；【高难度】

-- 查询和“002”号的同学学习的课程完全相同的其他同学学号和姓名；【高难度】
   -- 002号学习的课程
   -- count(1) == 002的课程count(1)
   -- left JOIN student 拼接姓名和学号
-- 数量相同学生ID
select student_id, course_id, count(1) from score GROUP BY student_id having count(1) =
(select count(1) from score where student_id = 2 )
-- 课程相同
select student_id, course_id from score where course_id in
(select DISTINCT course_id from score where student_id = 2) GROUP BY student_id
-- 综合完成
 select student_id,sname from score left join student on score.student_id = student.sid where student_id in (select student_id from score  where student_id != 1 group by student_id HAVING count(course_id) = (select count(1) from score where student_id = 1)) and course_id in (select course_id from score where student_id = 1) group by student_id HAVING count(course_id) = (select count(1) from score where student_id = 1)

-- 删除学习“叶平”老师课的score表记录；

delete from score where course_id in (
select cid from course left join teacher on course.teacher_id = teacher.tid where teacher.name = '叶平') 

[更多参考] http://www.cnblogs.com/wupeiqi/articles/5729934.html  

[更多参考] http://www.cnblogs.com/wupeiqi/articles/5748496.html