MySQL練習題


MySQL測試題

一、表關系

請創建如下表,並創建相關約束

二、操作表

1、自行創建測試數據

2、查詢“生物”課程比“物理”課程成績高的所有學生的學號;

3、查詢平均成績大於60分的同學的學號和平均成績; 

4、查詢所有同學的學號、姓名、選課數、總成績;

5、查詢姓“李”的老師的個數;

6、查詢沒學過“葉平”老師課的同學的學號、姓名;

7、查詢學過“001”並且也學過編號“002”課程的同學的學號、姓名;

8、查詢學過“葉平”老師所教的所有課的同學的學號、姓名;

9、查詢課程編號“002”的成績比課程編號“001”課程低的所有同學的學號、姓名;

10、查詢有課程成績小於60分的同學的學號、姓名;

11、查詢沒有學全所有課的同學的學號、姓名;

12、查詢至少有一門課與學號為“001”的同學所學相同的同學的學號和姓名;

13、查詢至少學過學號為“001”同學所選課程中任意一門課的其他同學學號和姓名;

14、查詢和“002”號的同學學習的課程完全相同的其他同學學號和姓名;

15、刪除學習“葉平”老師課的SC表記錄;

16、向SC表中插入一些記錄,這些記錄要求符合以下條件:①沒有上過編號“002”課程的同學學號;②插入“002”號課程的平均成績; 

17、按平均成績從低到高顯示所有學生的“語文”、“數學”、“英語”三門的課程成績,按如下形式顯示: 學生ID,語文,數學,英語,有效課程數,有效平均分;

18、查詢各科成績最高和最低的分:以如下形式顯示:課程ID,最高分,最低分;

19、按各科平均成績從低到高和及格率的百分數從高到低順序;

20、課程平均分從高到低顯示(現實任課老師);

21、查詢各科成績前三名的記錄:(不考慮成績並列情況) 

22、查詢每門課程被選修的學生數;

23、查詢出只選修了一門課程的全部學生的學號和姓名;

24、查詢男生、女生的人數;

25、查詢姓“張”的學生名單;

26、查詢同名同姓學生名單,並統計同名人數;

27、查詢每門課程的平均成績,結果按平均成績升序排列,平均成績相同時,按課程號降序排列;

28、查詢平均成績大於85的所有學生的學號、姓名和平均成績;

29、查詢課程名稱為“數學”,且分數低於60的學生姓名和分數;

30、查詢課程編號為003且課程成績在80分以上的學生的學號和姓名; 

31、求選了課程的學生人數

32、查詢選修“楊艷”老師所授課程的學生中,成績最高的學生姓名及其成績;

33、查詢各個課程及相應的選修人數;

34、查詢不同課程但成績相同的學生的學號、課程號、學生成績;

35、查詢每門課程成績最好的前兩名;

36、檢索至少選修兩門課程的學生學號;

37、查詢全部學生都選修的課程的課程號和課程名;

38、查詢沒學過“葉平”老師講授的任一門課程的學生姓名;

39、查詢兩門以上不及格課程的同學的學號及其平均成績;

40、檢索“004”課程分數小於60,按分數降序排列的同學學號;

41、刪除“002”同學的“001”課程的成績;

MySQL練習題參考答案

 

導出現有數據庫數據:

  • mysqldump -u用戶名 -p密碼 數據庫名稱 >導出文件路徑           # 結構+數據
  • mysqldump -u用戶名 -p密碼 -d 數據庫名稱 >導出文件路徑       # 結構 

導入現有數據庫數據:

  • mysqldump -uroot -p密碼  數據庫名稱 < 文件路徑  
Navicat Premium Data Transfer

 Source Server         : localhost
 Source Server Type    : MySQL
 Source Server Version : 50624
 Source Host           : localhost
 Source Database       : sqlexam

 Target Server Type    : MySQL
 Target Server Version : 50624
 File Encoding         : utf-8

 Date: 10/21/2016 06:46:46 AM
*/

SET NAMES utf8;
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`
-- ----------------------------
BEGIN;
INSERT INTO `class` VALUES ('1', '三年二班'), ('2', '三年三班'), ('3', '一年二班'), ('4', '二年九班');
COMMIT;

-- ----------------------------
--  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`
-- ----------------------------
BEGIN;
INSERT INTO `course` VALUES ('1', '生物', '1'), ('2', '物理', '2'), ('3', '體育', '3'), ('4', '美術', '2');
COMMIT;

-- ----------------------------
--  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`
-- ----------------------------
BEGIN;
INSERT INTO `score` VALUES ('1', '1', '1', '10'), ('2', '1', '2', '9'), ('5', '1', '4', '66'), ('6', '2', '1', '8'), ('8', '2', '3', '68'), ('9', '2', '4', '99'), ('10', '3', '1', '77'), ('11', '3', '2', '66'), ('12', '3', '3', '87'), ('13', '3', '4', '99'), ('14', '4', '1', '79'), ('15', '4', '2', '11'), ('16', '4', '3', '67'), ('17', '4', '4', '100'), ('18', '5', '1', '79'), ('19', '5', '2', '11'), ('20', '5', '3', '67'), ('21', '5', '4', '100'), ('22', '6', '1', '9'), ('23', '6', '2', '100'), ('24', '6', '3', '67'), ('25', '6', '4', '100'), ('26', '7', '1', '9'), ('27', '7', '2', '100'), ('28', '7', '3', '67'), ('29', '7', '4', '88'), ('30', '8', '1', '9'), ('31', '8', '2', '100'), ('32', '8', '3', '67'), ('33', '8', '4', '88'), ('34', '9', '1', '91'), ('35', '9', '2', '88'), ('36', '9', '3', '67'), ('37', '9', '4', '22'), ('38', '10', '1', '90'), ('39', '10', '2', '77'), ('40', '10', '3', '43'), ('41', '10', '4', '87'), ('42', '11', '1', '90'), ('43', '11', '2', '77'), ('44', '11', '3', '43'), ('45', '11', '4', '87'), ('46', '12', '1', '90'), ('47', '12', '2', '77'), ('48', '12', '3', '43'), ('49', '12', '4', '87'), ('52', '13', '3', '87');
COMMIT;

-- ----------------------------
--  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`
-- ----------------------------
BEGIN;
INSERT INTO `student` VALUES ('1', '', '1', '理解'), ('2', '', '1', '鋼蛋'), ('3', '', '1', '張三'), ('4', '', '1', '張一'), ('5', '', '1', '張二'), ('6', '', '1', '張四'), ('7', '', '2', '鐵錘'), ('8', '', '2', '李三'), ('9', '', '2', '李一'), ('10', '', '2', '李二'), ('11', '', '2', '李四'), ('12', '', '3', '如花'), ('13', '', '3', '劉三'), ('14', '', '3', '劉一'), ('15', '', '3', '劉二'), ('16', '', '3', '劉四');
COMMIT;

-- ----------------------------
--  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`
-- ----------------------------
BEGIN;
INSERT INTO `teacher` VALUES ('1', '張磊老師'), ('2', '李平老師'), ('3', '劉海燕老師'), ('4', '朱雲海老師'), ('5', '李傑老師');
COMMIT;

SET FOREIGN_KEY_CHECKS = 1;
表數據結構
  1 2、查詢“生物”課程比“物理”課程成績高的所有學生的學號;
  2 思路:
  3     獲取所有有生物課程的人(學號,成績) - 臨時表
  4     獲取所有有物理課程的人(學號,成績) - 臨時表
  5     根據【學號】連接兩個臨時表:
  6         學號  物理成績   生物成績
  7  
  8     然后再進行篩選
  9  
 10         select A.student_id,sw,ty from
 11  
 12         (select student_id,num as sw from score left join course on score.course_id = course.cid where course.cname = '生物') as A
 13  
 14         left join
 15  
 16         (select student_id,num  as ty from score left join course on score.course_id = course.cid where course.cname = '體育') as B
 17  
 18         on A.student_id = B.student_id where sw > if(isnull(ty),0,ty);
 19  
 20 3、查詢平均成績大於60分的同學的學號和平均成績; 
 21     思路:
 22         根據學生分組,使用avg獲取平均值,通過having對avg進行篩選
 23  
 24         select student_id,avg(num) from score group by student_id having avg(num) > 60
 25  
 26 4、查詢所有同學的學號、姓名、選課數、總成績;
 27  
 28     select score.student_id,sum(score.num),count(score.student_id),student.sname 
 29     from
 30         score left join student on score.student_id = student.sid   
 31     group by score.student_id
 32  
 33 5、查詢姓“李”的老師的個數;
 34     select count(tid) from teacher where tname like '李%'
 35  
 36     select count(1) from (select tid from teacher where tname like '李%') as B
 37  
 38 6、查詢沒學過“葉平”老師課的同學的學號、姓名;
 39     思路:
 40         先查到“李平老師”老師教的所有課ID
 41         獲取選過課的所有學生ID
 42         學生表中篩選
 43     select * from student where sid not in (
 44         select DISTINCT student_id from score where score.course_id in (
 45             select cid from course left join teacher on course.teacher_id = teacher.tid where tname = '李平老師'
 46         )
 47     )
 48  
 49 7、查詢學過“001”並且也學過編號“002”課程的同學的學號、姓名;
 50     思路:
 51         先查到既選擇001又選擇002課程的所有同學
 52         根據學生進行分組,如果學生數量等於2表示,兩門均已選擇
 53  
 54     select student_id,sname from
 55  
 56     (select student_id,course_id from score where course_id = 1 or course_id = 2) as B
 57       
 58     left join student on B.student_id = student.sid group by student_id HAVING count(student_id) > 1
 59  
 60  
 61 8、查詢學過“葉平”老師所教的所有課的同學的學號、姓名;
 62  
 63     同上,只不過將001和002變成 in (葉平老師的所有課)
 64  
 65 9、查詢課程編號“002”的成績比課程編號“001”課程低的所有同學的學號、姓名;
 66     同第1題
 67  
 68  
 69 10、查詢有課程成績小於60分的同學的學號、姓名;
 70          
 71     select sid,sname from student where sid in (
 72         select distinct student_id from score where num < 60
 73     )
 74  
 75 11、查詢沒有學全所有課的同學的學號、姓名;
 76     思路:
 77         在分數表中根據學生進行分組,獲取每一個學生選課數量
 78         如果數量 == 總課程數量,表示已經選擇了所有課程
 79  
 80         select student_id,sname 
 81         from score left join student on score.student_id = student.sid 
 82         group by student_id HAVING count(course_id) = (select count(1) from course)
 83  
 84  
 85 12、查詢至少有一門課與學號為“001”的同學所學相同的同學的學號和姓名;
 86     思路:
 87         獲取 001 同學選擇的所有課程
 88         獲取課程在其中的所有人以及所有課程
 89         根據學生篩選,獲取所有學生信息
 90         再與學生表連接,獲取姓名
 91  
 92         select student_id,sname, count(course_id) 
 93         from score left join student on score.student_id = student.sid
 94         where student_id != 1 and course_id in (select course_id from score where student_id = 1) group by student_id
 95  
 96 13、查詢至少學過學號為“001”同學所有課的其他同學學號和姓名;
 97         先找到和001的學過的所有人
 98         然后個數 = 001所有學科     ==》 其他人可能選擇的更多
 99  
100         select student_id,sname, count(course_id) 
101         from score left join student on score.student_id = student.sid
102         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(course_id) from score where student_id = 1)
103  
104 14、查詢和“002”號的同學學習的課程完全相同的其他同學學號和姓名;
105          
106         個數相同
107         002學過的也學過
108  
109         select student_id,sname from score left join student on score.student_id = student.sid where student_id in (
110             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)
111         ) 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)
112  
113  
114 15、刪除學習“葉平”老師課的score表記錄;
115  
116     delete from score where course_id in (
117         select cid from course left join teacher on course.teacher_id = teacher.tid where teacher.name = '葉平'
118     )
119  
120 16、向SC表中插入一些記錄,這些記錄要求符合以下條件:①沒有上過編號“002”課程的同學學號;②插入“002”號課程的平均成績; 
121     思路:
122         由於insert 支持  
123                 inset into tb1(xx,xx) select x1,x2 from tb2;
124         所有,獲取所有沒上過002課的所有人,獲取002的平均成績
125  
126     insert into score(student_id, course_id, num) select sid,2,(select avg(num) from score where course_id = 2) 
127     from student where sid not in (
128         select student_id from score where course_id = 2
129     )
130      
131 17、按平均成績從低到高 顯示所有學生的“語文”、“數學”、“英語”三門的課程成績,按如下形式顯示: 學生ID,語文,數學,英語,有效課程數,有效平均分;
132     select sc.student_id,
133         (select num from score left join course on score.course_id = course.cid where course.cname = "生物" and score.student_id=sc.student_id) as sy,
134         (select num from score left join course on score.course_id = course.cid where course.cname = "物理" and score.student_id=sc.student_id) as wl,
135         (select num from score left join course on score.course_id = course.cid where course.cname = "體育" and score.student_id=sc.student_id) as ty,
136         count(sc.course_id),
137         avg(sc.num)
138     from score as sc
139     group by student_id desc        
140  
141 18、查詢各科成績最高和最低的分:以如下形式顯示:課程ID,最高分,最低分;
142      
143     select course_id, max(num) as max_num, min(num) as min_num from score group by course_id;
144  
145 19、按各科平均成績從低到高和及格率的百分數從高到低順序;
146     思路:case when .. then
147     select course_id, avg(num) as avgnum,sum(case when score.num > 60 then 1 else 0 END)/count(1)*100 as percent from score group by course_id order by avgnum asc,percent desc;
148  
149 20、課程平均分從高到低顯示(現實任課老師);
150  
151     select avg(if(isnull(score.num),0,score.num)),teacher.tname from course 
152     left join score on course.cid = score.course_id 
153     left join teacher on course.teacher_id = teacher.tid
154  
155     group by score.course_id
156  
157  
158 21、查詢各科成績前三名的記錄:(不考慮成績並列情況) 
159     select score.sid,score.course_id,score.num,T.first_num,T.second_num from score left join
160     (
161     select
162         sid,
163         (select num from score as s2 where s2.course_id = s1.course_id order by num desc limit 0,1) as first_num,
164         (select num from score as s2 where s2.course_id = s1.course_id order by num desc limit 3,1) as second_num
165     from
166         score as s1
167     ) as T
168     on score.sid =T.sid
169     where score.num <= T.first_num and score.num >= T.second_num
170  
171 22、查詢每門課程被選修的學生數;
172      
173     select course_id, count(1) from score group by course_id;
174  
175 23、查詢出只選修了一門課程的全部學生的學號和姓名;
176     select student.sid, student.sname, count(1) from score
177  
178     left join student on score.student_id  = student.sid
179  
180      group by course_id having count(1) = 1
181  
182  
183 24、查詢男生、女生的人數;
184     select * from
185     (select count(1) as man from student where gender='') as A ,
186     (select count(1) as feman from student where gender='') as B 
187  
188 25、查詢姓“張”的學生名單;
189     select sname from student where sname like '張%';
190  
191 26、查詢同名同姓學生名單,並統計同名人數;
192  
193     select sname,count(1) as count from student group by sname;
194  
195 27、查詢每門課程的平均成績,結果按平均成績升序排列,平均成績相同時,按課程號降序排列;
196     select course_id,avg(if(isnull(num), 0 ,num)) as avg from score group by course_id order by avg     asc,course_id desc;
197  
198 28、查詢平均成績大於85的所有學生的學號、姓名和平均成績;
199  
200     select student_id,sname, avg(if(isnull(num), 0 ,num)) from score left join student on score.student_id = student.sid group by student_id;
201  
202 29、查詢課程名稱為“數學”,且分數低於60的學生姓名和分數;
203  
204     select student.sname,score.num from score 
205     left join course on score.course_id = course.cid
206     left join student on score.student_id = student.sid
207     where score.num < 60 and course.cname = '生物'
208  
209 30、查詢課程編號為003且課程成績在80分以上的學生的學號和姓名; 
210     select * from score where score.student_id = 3 and score.num > 80
211  
212 31、求選了課程的學生人數
213  
214     select count(distinct student_id) from score
215  
216     select count(c) from (
217         select count(student_id) as c from score group by student_id) as A
218  
219 32、查詢選修“楊艷”老師所授課程的學生中,成績最高的學生姓名及其成績;
220      
221     select sname,num from score 
222     left join student on score.student_id = student.sid
223     where score.course_id in (select course.cid from course left join teacher on course.teacher_id = teacher.tid where tname='張磊老師') order by num desc limit 1;
224  
225 33、查詢各個課程及相應的選修人數;
226     select course.cname,count(1) from score
227     left join course on score.course_id = course.cid
228     group by course_id;
229  
230  
231 34、查詢不同課程但成績相同的學生的學號、課程號、學生成績;
232     select DISTINCT s1.course_id,s2.course_id,s1.num,s2.num from score as s1, score as s2 where s1.num = s2.num and s1.course_id != s2.course_id;
233  
234 35、查詢每門課程成績最好的前兩名;
235  
236     select score.sid,score.course_id,score.num,T.first_num,T.second_num from score left join
237     (
238     select
239         sid,
240         (select num from score as s2 where s2.course_id = s1.course_id order by num desc limit 0,1) as first_num,
241         (select num from score as s2 where s2.course_id = s1.course_id order by num desc limit 1,1) as second_num
242     from
243         score as s1
244     ) as T
245     on score.sid =T.sid
246     where score.num <= T.first_num and score.num >= T.second_num
247  
248 36、檢索至少選修兩門課程的學生學號;
249     select student_id from score group by student_id having count(student_id) > 1
250  
251 37、查詢全部學生都選修的課程的課程號和課程名;
252     select course_id,count(1) from score group by course_id having count(1) = (select count(1) from student);
253  
254 38、查詢沒學過“葉平”老師講授的任一門課程的學生姓名;
255     select student_id,student.sname from score 
256     left join student on score.student_id = student.sid
257     where score.course_id not in (
258         select cid from course left join teacher on course.teacher_id = teacher.tid where tname = '張磊老師'
259     ) 
260     group by student_id
261  
262 39、查詢兩門以上不及格課程的同學的學號及其平均成績;
263  
264     select student_id,count(1) from score where num < 60 group by student_id having count(1) > 2
265  
266 40、檢索“004”課程分數小於60,按分數降序排列的同學學號;
267     select student_id from score where num< 60 and course_id = 4 order by num desc;
268  
269 41、刪除“002”同學的“001”課程的成績;
270     delete from score where course_id = 1 and student_id = 2

 


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