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<code>1.sampdb所用到的表格</code>
<code> </code><code>sampdb关于学生考试的表格总共有四张,如下</code>
<code>学生信息表</code>
<code>MariaDB [sampdb]> </code><code>select</code> <code>* from student;</code>
<code>+-----------+-----+------------+</code>
<code>| name | sex | student_id | </code>
<code>+-----------+-----+------------+ </code>
<code>| Megan | F | 1 |</code>
<code>| Joseph | M | 2 |</code>
<code>| Kyle | M | 3 |</code>
<code>学生成绩表</code>
<code>MariaDB [sampdb]> </code><code>select</code> <code>* from score;</code>
<code>+------------+----------+-------+</code>
<code>| student_id | event_id | score |</code>
<code>| 1 | 1 | 20 |</code>
<code>| 3 | 1 | 20 |</code>
<code>| 4 | 1 | 18 |</code>
<code>测试考试统计表</code>
<code>MariaDB [sampdb]> </code><code>select</code> <code>* from grade_event;</code>
<code>+------------+----------+----------+</code>
<code>| </code><code>date</code> <code>| category | event_id |</code>
<code>| 2008-09-03 | Q | 1 |</code>
<code>| 2008-09-06 | Q | 2 |</code>
<code>| 2008-09-09 | T | 3 |</code>
<code>| 2008-09-16 | Q | 4 |</code>
<code>| 2008-09-23 | Q | 5 |</code>
<code>| 2008-10-01 | T | 6 |</code>
<code>学生缺勤表</code>
<code>MariaDB [sampdb]> </code><code>select</code> <code>* from absence;</code>
<code>+------------+------------+</code>
<code>| student_id | </code><code>date</code> <code>|</code>
<code>| 3 | 2008-09-03 |</code>
<code>| 5 | 2008-09-03 |</code>
<code>| 10 | 2008-09-06 |</code>
<code>| 10 | 2008-09-09 |</code>
<code>| 17 | 2008-09-07 |</code>
<code>| 20 | 2008-09-07 |</code>
<code>2.表格结构索引</code>
<code> </code><code>student</code>
<code> </code><code>| student | CREATE TABLE `student` (</code>
<code> </code><code>`name` varchar(20) NOT NULL,</code>
<code> </code><code>`sex` enum(</code><code>'F'</code><code>,</code><code>'M'</code><code>) NOT NULL,</code>
<code> </code><code>`student_id` int(10) unsigned NOT NULL AUTO_INCREMENT,</code>
<code> </code><code>PRIMARY KEY (`student_id`)</code>
<code>) ENGINE=InnoDB AUTO_INCREMENT=32 DEFAULT CHARSET=latin1 |</code>
<code> </code><code>score</code>
<code> </code>
<code> </code><code>| score | CREATE TABLE `score` (</code>
<code> </code><code>`student_id` int(10) unsigned NOT NULL,</code>
<code> </code><code>`event_id` int(10) unsigned NOT NULL,</code>
<code> </code><code>`score` int(11) NOT NULL,</code>
<code> </code><code>PRIMARY KEY (`event_id`,`student_id`),</code>
<code> </code><code>KEY `student_id` (`student_id`),</code>
<code> </code><code>CONSTRAINT `score_ibfk_1` FOREIGN KEY (`event_id`) REFERENCES `grade_event` (`event_id`),</code>
<code> </code><code>CONSTRAINT `score_ibfk_2` FOREIGN KEY (`student_id`) REFERENCES `student` (`student_id`)</code>
<code>) ENGINE=InnoDB DEFAULT CHARSET=latin1 |</code>
<code> </code><code>grade_event</code>
<code> </code><code>| grade_event | CREATE TABLE `grade_event` (</code>
<code> </code><code>`</code><code>date</code><code>` </code><code>date</code> <code>NOT NULL,</code>
<code> </code><code>`category` enum(</code><code>'T'</code><code>,</code><code>'Q'</code><code>) NOT NULL,</code>
<code> </code><code>`event_id` int(10) unsigned NOT NULL AUTO_INCREMENT,</code>
<code> </code><code>PRIMARY KEY (`event_id`)</code>
<code>) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=latin1 |</code>
<code> </code><code>absence</code>
<code> </code><code>| absence | CREATE TABLE `absence` (</code>
<code> </code><code>PRIMARY KEY (`student_id`,`</code><code>date</code><code>`),</code>
<code> </code><code>CONSTRAINT `absence_ibfk_1` FOREIGN KEY (`student_id`) REFERENCES `student` (`student_id`)</code>
<code>3.检索数据</code>
<code>检索统计参加event_id为1考试的学生人数</code>
<code>MariaDB [sampdb]> </code><code>select</code> <code>count(student_id) from score where event_id=1;</code>
<code>+-------------------+</code>
<code>| count(student_id) |</code>
<code>| 29 |</code>
<code>1 row </code><code>in</code> <code>set</code> <code>(0.00 sec)</code>
<code> </code><code>列出参加event_id为1考试的学生名单</code>
<code>MariaDB [sampdb]> </code><code>select</code> <code>group_concat(student.name) from student left </code><code>join</code> <code>score on student.student_id=score.student_id </code>
<code>where score.event_id=1;</code>
<code>+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+</code>
<code>| group_concat(student.name) |</code>
<code>| Megan,Kyle,Katie,Abby,Nathan,Liesl,Ian,Colin,Peter,Michael,Thomas,Ben,Aubrey,Rebecca,Will,Max,Rianne,Avery,Lauren,</code>
<code>Becca,Gregory,Sarah,Robbie,Keaton,Carter,Teddy,Gabrielle,Grace,Emily |</code>
<code>+---------</code>
<code>检索统计未参加event_id为1考试的学生人数</code>
<code>MariaDB [sampdb]> </code><code>select</code> <code>count(student.student_id) from student left </code><code>join</code> <code>(</code><code>select</code> <code>* from score where event_id=1) as score1 on student.student_id=score1.student_id where score1.score is null;</code>
<code>+---------------------------+</code>
<code>| count(student.student_id) |</code>
<code>| 2 |</code>
<code>列出未参加event_id为1考试的学生名单</code>
<code>MariaDB [sampdb]> </code><code>select</code> <code>group_concat(student.name) from student left </code><code>join</code> <code>(</code><code>select</code> <code>* from score where event_id=1)</code>
<code> </code><code>as score1 on student.student_id=score1.student_id where score1.score is null;</code>
<code>+----------------------------+</code>
<code>| group_concat(student.name) |</code>
<code>| Joseph,Devri |</code>
<code>检索参加event_id为1考试的学生最高成绩,平均成绩,最低成绩</code>
<code> </code><code>MariaDB [sampdb]> </code><code>select</code> <code>max(score1.score),avg(score1.score),min(score1.score) from student left </code><code>join</code> <code>(</code><code>select</code> <code>* </code>
<code>from score where event_id=1) as score1 on student.student_id=score1.student_id;</code>
<code>+-------------------+-------------------+-------------------+</code>
<code>| max(score1.score) | avg(score1.score) | min(score1.score) |</code>
<code>| 20 | 15.1379 | 9 |</code>
<code>检索参加event_id为1考试的最高成绩的学生名字</code>
<code>select</code> <code>student.name from student left </code><code>join</code> <code>score on student.student_id=score.student_id where </code>
<code>score.event_id=1 and score=(</code><code>select</code> <code>max(score) from score where event_id=1);</code>
<code>+--------+</code>
<code>| name |</code>
<code>| Megan |</code>
<code>| Kyle |</code>
<code>| Aubrey |</code>
<code>| Max |</code>
<code>减速参加event_id为1考试的最低成绩的学生名字</code>
<code>MariaDB [sampdb]> </code><code>select</code> <code>student.name,score from student left </code><code>join</code> <code>score on student.student_id=score.student_id where score.event_id=1 and score=(</code><code>select</code> <code>min(score) from score where event_id=1);</code>
<code>+--------+-------+</code>
<code>| name | score |</code>
<code>| Will | 9 |</code>
<code>| Rianne | 9 |</code>
<code>| Avery | 9 |</code>
<code>3 rows </code><code>in</code> <code>set</code> <code>(0.00 sec)</code>
<code>4.写一个存储过程,根据考试ID,列出这次考试多少人参加,列出参加学生的名字,多少人缺席,列出缺席的学生名字,</code>
<code>列出考试的最高成绩的获得者的名字和最高成绩,最低成绩的获得者名字和最低成绩,平均成绩。</code>
<code>create procedure id_in(num int)</code>
<code>begin</code>
<code>select</code> <code>concat(</code><code>'考试人数'</code><code>),count(student_id) from score where event_id=num; </code>
<code>select</code> <code>concat(</code><code>'参加考试名单'</code><code>),group_concat(name) from student left </code><code>join</code> <code>score on student.student_id=score.student_id where event_id=num; </code>
<code>select</code> <code>concat(</code><code>'缺席考试人数'</code><code>),count(name) from student left </code><code>join</code> <code>(</code><code>select</code> <code>* from score where event_id=num) as score1 on student.student_id=score1.student_id where score1.score is null; </code>
<code>select</code> <code>concat(</code><code>'缺席考试名单'</code><code>),group_concat(name) from student left </code><code>join</code> <code>(</code><code>select</code> <code>* from score where event_id=num) as score1 on student.student_id=score1.student_id where score1.score is null; </code>
<code>select</code> <code>concat(</code><code>'最高成绩学生名单'</code><code>),group_concat(student.name) from student left </code><code>join</code> <code>score on student.student_id=score.student_id where score.event_id=num and score=(</code><code>select</code> <code>max(score) from score where score.event_id=num); </code>
<code>select</code> <code>concat(</code><code>'最 低成绩学生名单'</code><code>),group_concat(student.name) from student left </code><code>join</code> <code>score on student.student_id=score.student_id where score.event_id=num and score=(</code><code>select</code> <code>min(score) from score where score.event_id=num); </code>
<code>select</code> <code>concat(</code><code>'最高成绩'</code><code>),max(score1.score),concat(</code><code>'平均成绩'</code><code>),avg(score1.score),concat(</code><code>'最低成绩'</code><code>),min(score1.score) from student left </code><code>join</code> <code>(</code><code>select</code> <code>* from score where score.event_id=num) as score1 on student.student_id=score1.student_id; </code>
<code>end$</code>
<code>结果:</code>
<code>MariaDB [sampdb]> call id_in(1);</code>
<code>+------------------------+-------------------+</code>
<code>| concat(</code><code>'考试人数'</code><code>) | count(student_id) |</code>
<code>| 考试人数 | 29 |</code>
<code>1 row </code><code>in</code> <code>set</code> <code>(0.01 sec)</code>
<code>+------------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+</code>
<code>| concat(</code><code>'参加考试名单'</code><code>) | group_concat(name) |</code>
<code>| 参加考试名单 | Megan,Kyle,Katie,Abby,Nathan,Liesl,Ian,Colin,Peter,Michael,Thomas,Ben,Aubrey,Rebecca,Will,Max,Rianne,Avery,Lauren,Becca,Gregory,Sarah,Robbie,Keaton,Carter,Teddy,Gabrielle,Grace,Emily |</code>
<code>+------------------------------+-------------+</code>
<code>| concat(</code><code>'缺席考试人数'</code><code>) | count(name) |</code>
<code>| 缺席考试人数 | 2 |</code>
<code>+------------------------------+--------------------+</code>
<code>| concat(</code><code>'缺席考试名单'</code><code>) | group_concat(name) |</code>
<code>| 缺席考试名单 | Joseph,Devri |</code>
<code>+------------------------------------+----------------------------+</code>
<code>| concat(</code><code>'最高成绩学生名单'</code><code>) | group_concat(student.name) |</code>
<code>| 最高成绩学生名单 | Megan,Kyle,Aubrey,Max |</code>
<code>+-------------------------------------+----------------------------+</code>
<code>| concat(</code><code>'最 低成绩学生名单'</code><code>) | group_concat(student.name) |</code>
<code>| 最 低成绩学生名单 | Will,Rianne,Avery |</code>
<code>+------------------------+-------------------+------------------------+-------------------+------------------------+-------------------+</code>
<code>| concat(</code><code>'最高成绩'</code><code>) | max(score1.score) | concat(</code><code>'平均成绩'</code><code>) | avg(score1.score) | concat(</code><code>'最低成绩'</code><code>) | min(score1.score) |</code>
<code>| 最高成绩 | 20 | 平均成绩 | 15.1379 | 最低成绩 | 9 |</code>
<code>Query OK, 0 rows affected (0.01 sec)</code>
本文转自 am2012 51CTO博客,原文链接:http://blog.51cto.com/goome/1964559