这期内容当中小编将会给大家带来有关如何进行mysql多表查询，文章内容丰富且以专业的角度为大家分析和叙述，阅读完这篇文章希望大家可以有所收获。

一、准备数据库

init.sql文件内容如下：

/*数据导入：NavicatPremiumDataTransferSourceServer:localhostSourceServerType:MySQLSourceServerVersion:50624SourceHost:localhostSourceDatabase:sqlexamTargetServerType:MySQLTargetServerVersion:50624FileEncoding:utf-8Date:10/21/201606:46:46AM*/SETNAMESutf8;SETFOREIGN_KEY_CHECKS=0;--------------------------------Tablestructurefor`class`------------------------------DROPTABLEIFEXISTS`class`;CREATETABLE`class`(`cid`int(11)NOTNULLAUTO_INCREMENT,`caption`varchar(32)NOTNULL,PRIMARYKEY(`cid`))ENGINE=InnoDBAUTO_INCREMENT=5DEFAULTCHARSET=utf8;--------------------------------Recordsof`class`------------------------------BEGIN;INSERTINTO`class`VALUES('1','三年二班'),('2','三年三班'),('3','一年二班'),('4','二年九班');COMMIT;--------------------------------Tablestructurefor`course`------------------------------DROPTABLEIFEXISTS`course`;CREATETABLE`course`(`cid`int(11)NOTNULLAUTO_INCREMENT,`cname`varchar(32)NOTNULL,`teacher_id`int(11)NOTNULL,PRIMARYKEY(`cid`),KEY`fk_course_teacher`(`teacher_id`),CONSTRAINT`fk_course_teacher`FOREIGNKEY(`teacher_id`)REFERENCES`teacher`(`tid`))ENGINE=InnoDBAUTO_INCREMENT=5DEFAULTCHARSET=utf8;--------------------------------Recordsof`course`------------------------------BEGIN;INSERTINTO`course`VALUES('1','生物','1'),('2','物理','2'),('3','体育','3'),('4','美术','2');COMMIT;--------------------------------Tablestructurefor`score`------------------------------DROPTABLEIFEXISTS`score`;CREATETABLE`score`(`sid`int(11)NOTNULLAUTO_INCREMENT,`student_id`int(11)NOTNULL,`course_id`int(11)NOTNULL,`num`int(11)NOTNULL,PRIMARYKEY(`sid`),KEY`fk_score_student`(`student_id`),KEY`fk_score_course`(`course_id`),CONSTRAINT`fk_score_course`FOREIGNKEY(`course_id`)REFERENCES`course`(`cid`),CONSTRAINT`fk_score_student`FOREIGNKEY(`student_id`)REFERENCES`student`(`sid`))ENGINE=InnoDBAUTO_INCREMENT=53DEFAULTCHARSET=utf8;--------------------------------Recordsof`score`------------------------------BEGIN;INSERTINTO`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;--------------------------------Tablestructurefor`student`------------------------------DROPTABLEIFEXISTS`student`;CREATETABLE`student`(`sid`int(11)NOTNULLAUTO_INCREMENT,`gender`char(1)NOTNULL,`class_id`int(11)NOTNULL,`sname`varchar(32)NOTNULL,PRIMARYKEY(`sid`),KEY`fk_class`(`class_id`),CONSTRAINT`fk_class`FOREIGNKEY(`class_id`)REFERENCES`class`(`cid`))ENGINE=InnoDBAUTO_INCREMENT=17DEFAULTCHARSET=utf8;--------------------------------Recordsof`student`------------------------------BEGIN;INSERTINTO`student`VALUES('1','男','1','理解'),('2','女','1','钢蛋'),('3','男','1','张三'),('4','男','1','张一'),('5','女','1','张二'),('6','男','1','张四'),('7','女','2','铁锤'),('8','男','2','李三'),('9','男','2','李一'),('10','女','2','李二'),('11','男','2','李四'),('12','女','3','如花'),('13','男','3','刘三'),('14','男','3','刘一'),('15','女','3','刘二'),('16','男','3','刘四');COMMIT;--------------------------------Tablestructurefor`teacher`------------------------------DROPTABLEIFEXISTS`teacher`;CREATETABLE`teacher`(`tid`int(11)NOTNULLAUTO_INCREMENT,`tname`varchar(32)NOTNULL,PRIMARYKEY(`tid`))ENGINE=InnoDBAUTO_INCREMENT=6DEFAULTCHARSET=utf8;--------------------------------Recordsof`teacher`------------------------------BEGIN;INSERTINTO`teacher`VALUES('1','张磊老师'),('2','李平老师'),('3','刘海燕老师'),('4','朱云海老师'),('5','李杰老师');COMMIT;SETFOREIGN_KEY_CHECKS=1;

1、创建数据库并导入数据

mysql>createdatabasedb1;

mysql> create database db1;
mysql> use db1;
mysql> source /root/init.sql

2、查看表

mysql>showtables;+---------------+|Tables_in_db1|+---------------+|class||course||score||student||teacher|+---------------+mysql>select*fromclass;+-----+--------------+|cid|caption|+-----+--------------+|1|三年二班||2|三年三班||3|一年二班||4|二年九班|+-----+--------------+mysql>select*fromcourse;+-----+--------+------------+|cid|cname|teacher_id|+-----+--------+------------+|1|生物|1||2|物理|2||3|体育|3||4|美术|2|+-----+--------+------------+mysql>select*fromteacher;+-----+-----------------+|tid|tname|+-----+-----------------+|1|张磊老师||2|李平老师||3|刘海燕老师||4|朱云海老师||5|李杰老师|+-----+-----------------+mysql>select*fromstudent;+-----+--------+----------+--------+|sid|gender|class_id|sname|+-----+--------+----------+--------+|1|男|1|理解||2|女|1|钢蛋||3|男|1|张三||4|男|1|张一||5|女|1|张二||6|男|1|张四||7|女|2|铁锤||8|男|2|李三||9|男|2|李一||10|女|2|李二||11|男|2|李四||12|女|3|如花||13|男|3|刘三||14|男|3|刘一||15|女|3|刘二||16|男|3|刘四|+-----+--------+----------+--------+mysql>select*fromscore;+-----+------------+-----------+-----+|sid|student_id|course_id|num|+-----+------------+-----------+-----+|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|+-----+------------+-----------+-----+

二、操作练习

1、查询所有的课程的名称以及对应的任课老师姓名

SELECTcourse.cname,teacher.tnameFROMcourseINNERJOINteacherONcourse.teacher_id=teacher.tid;SELECTcourse.cname,teacher.tnameFROMcourseJOINteacherONcourse.teacher_id=teacher.tid;+--------+-----------------+|cname|tname|+--------+-----------------+|生物|张磊老师||物理|李平老师||美术|李平老师||体育|刘海燕老师|+--------+-----------------+

2、查询学生表中男女生各有多少人

SELECTgender性别,count(1)人数FROMstudentGROUPBYgender;+--------+--------+|性别|人数|+--------+--------+|女|6||男|10|+--------+--------+

3、查询物理成绩等于100的学生的姓名

SELECTstudent.snameFROMstudentWHEREsidIN(SELECTstudent_idFROMscoreINNERJOINcourseONscore.course_id=course.cidWHEREcourse.cname='物理'ANDscore.num=100);+--------+|sname|+--------+|张四||铁锤||李三|+--------+

4、查询平均成绩大于八十分的同学的姓名和平均成绩

SELECTstudent.sname,t1.avg_numFROMstudentINNERJOIN(SELECTstudent_id,avg(num)ASavg_numFROMscoreGROUPBYstudent_idHAVINGavg(num)>80)ASt1ONstudent.sid=t1.student_id;+--------+---------+|sname|avg_num|+--------+---------+|张三|82.2500||刘三|87.0000|+--------+---------+SELECTstudent.sname,avg(num)ASavg_numFROMscoreJOINstudentONstudent.sid=score.student_idGROUPBYstudent_idHAVINGavg_num>80;

5、查询所有学生的学号，姓名，选课数，总成绩

SELECTstudent.sid,student.sname,t1.course_num,t1.total_numFROMstudentLEFTJOIN(SELECTstudent_id,COUNT(course_id)course_num,sum(num)total_numFROMscoreGROUPBYstudent_id)ASt1ONstudent.sid=t1.student_id;+-----+--------+------------+-----------+|sid|sname|course_num|total_num|+-----+--------+------------+-----------+|1|理解|3|85||2|钢蛋|3|175||3|张三|4|329||4|张一|4|257||5|张二|4|257||6|张四|4|276||7|铁锤|4|264||8|李三|4|264||9|李一|4|268||10|李二|4|297||11|李四|4|297||12|如花|4|297||13|刘三|1|87||14|刘一|NULL|NULL||15|刘二|NULL|NULL||16|刘四|NULL|NULL|+-----+--------+------------+-----------+

6、 查询姓李老师的个数

SELECTcount(tid)FROMteacherWHEREtnameLIKE'李%';+------------+|count(tid)|+------------+|2|+------------+

7、 查询没有报李平老师课的学生姓名

SELECTstudent.snameFROMstudentWHEREsidNOTIN(SELECTDISTINCTstudent_idFROMscoreWHEREcourse_idIN(SELECTcourse.cidFROMcourseINNERJOINteacherONcourse.teacher_id=teacher.tidWHEREteacher.tname='李平老师'));+--------+|sname|+--------+|刘三||刘一||刘二||刘四|+--------+

8、 查询物理课程比生物课程高的学生的学号

SELECTt1.student_idFROM(SELECTstudent_id,numFROMscoreWHEREcourse_id=(SELECTcidFROMcourseWHEREcname='物理'))ASt1INNERJOIN(SELECTstudent_id,numFROMscoreWHEREcourse_id=(SELECTcidFROMcourseWHEREcname='生物'))ASt2ONt1.student_id=t2.student_idWHEREt1.num>t2.num;+------------+|student_id|+------------+|6||7||8|+------------+

9、 查询没有同时选修物理课程和体育课程的学生姓名

SELECTstudent.snameFROMstudentWHEREsidIN(SELECTstudent_idFROMscoreWHEREcourse_idIN(SELECTcidFROMcourseWHEREcname='物理'ORcname='体育')GROUPBYstudent_idHAVINGCOUNT(course_id)=1);+--------+|sname|+--------+|理解||钢蛋||刘三|+--------+

10、查询挂科超过两门(包括两门)的学生姓名和班级

SELECTstudent.sname,class.captionFROMstudentINNERJOIN(SELECTstudent_idFROMscoreWHEREnum<60GROUPBYstudent_idHAVINGcount(course_id)>=2)ASt1INNERJOINclassONstudent.sid=t1.student_idANDstudent.class_id=class.cid;+--------+--------------+|sname|caption|+--------+--------------+|理解|三年二班|+--------+--------------+

11、查询选修了所有课程的学生姓名

SELECTstudent.snameFROMstudentWHEREsidIN(SELECTstudent_idFROMscoreGROUPBYstudent_idHAVINGCOUNT(course_id)=(SELECTcount(cid)FROMcourse));+--------+|sname|+--------+|张三||张一||张二||张四||铁锤||李三||李一||李二||李四||如花|+--------+

12、查询李平老师教的课程的所有成绩记录

SELECT*FROMscoreWHEREcourse_idIN(SELECTcidFROMcourseINNERJOINteacherONcourse.teacher_id=teacher.tidWHEREteacher.tname='李平老师');+-----+------------+-----------+-----+|sid|student_id|course_id|num|+-----+------------+-----------+-----+|2|1|2|9||11|3|2|66||15|4|2|11||19|5|2|11||23|6|2|100||27|7|2|100||31|8|2|100||35|9|2|88||39|10|2|77||43|11|2|77||47|12|2|77||5|1|4|66||9|2|4|99||13|3|4|99||17|4|4|100||21|5|4|100||25|6|4|100||29|7|4|88||33|8|4|88||37|9|4|22||41|10|4|87||45|11|4|87||49|12|4|87|+-----+------------+-----------+-----+

13、查询全部学生都选修了的课程号和课程名

SELECTcid,cnameFROMcourseWHEREcidIN(SELECTcourse_idFROMscoreGROUPBYcourse_idHAVINGCOUNT(student_id)=(SELECTCOUNT(sid)FROMstudent));

14、查询每门课程被选修的次数

SELECTcourse_id,COUNT(student_id)FROMscoreGROUPBYcourse_id;+-----------+-------------------+|course_id|COUNT(student_id)|+-----------+-------------------+|1|12||2|11||3|12||4|12|+-----------+-------------------+

15、查询之选修了一门课程的学生姓名和学号

SELECTsid,snameFROMstudentWHEREsidIN(SELECTstudent_idFROMscoreGROUPBYstudent_idHAVINGCOUNT(course_id)=1);+-----+--------+|sid|sname|+-----+--------+|13|刘三|+-----+--------+

16、查询所有学生考出的成绩并按从高到低排序（成绩去重）

SELECTDISTINCTnumFROMscoreORDERBYnumDESC;+-----+|num|+-----+|100||99||91||90||88||87||79||77||68||67||66||43||22||11||10||9||8|+-----+

17、查询平均成绩大于85的学生姓名和平均成绩

SELECTsname,t1.avg_numFROMstudentINNERJOIN(SELECTstudent_id,avg(num)avg_numFROMscoreGROUPBYstudent_idHAVINGAVG(num)>85)t1ONstudent.sid=t1.student_id;+--------+---------+|sname|avg_num|+--------+---------+|刘三|87.0000|+--------+---------+

18、查询生物成绩不及格的学生姓名和对应生物分数

SELECTsname姓名,num生物成绩FROMscoreLEFTJOINcourseONscore.course_id=course.cidLEFTJOINstudentONscore.student_id=student.sidWHEREcourse.cname='生物'ANDscore.num<60;+--------+--------------+|姓名|生物成绩|+--------+--------------+|理解|10||钢蛋|8||张四|9||铁锤|9||李三|9|+--------+--------------+

19、查询在所有选修了李平老师课程的学生中，这些课程(李平老师的课程，不是所有课程)平均成绩最高的学生姓名

SELECTsnameFROMstudentWHEREsid=(SELECTstudent_idFROMscoreWHEREcourse_idIN(SELECTcourse.cidFROMcourseINNERJOINteacherONcourse.teacher_id=teacher.tidWHEREteacher.tname='李平老师')GROUPBYstudent_idORDERBYAVG(num)DESCLIMIT1);+--------+|sname|+--------+|张四|+--------+

20、查询每门课程成绩最好的前两名学生姓名

#查看每门课程按照分数排序的信息，为下列查找正确与否提供依据SELECT*FROMscoreORDERBYcourse_id,numDESC;+-----+------------+-----------+-----+|sid|student_id|course_id|num|+-----+------------+-----------+-----+|34|9|1|91||46|12|1|90||42|11|1|90||38|10|1|90||14|4|1|79||18|5|1|79||10|3|1|77||1|1|1|10||30|8|1|9||26|7|1|9||22|6|1|9||6|2|1|8||31|8|2|100||23|6|2|100||27|7|2|100||35|9|2|88||47|12|2|77||43|11|2|77||39|10|2|77||11|3|2|66||19|5|2|11||15|4|2|11||2|1|2|9||52|13|3|87||12|3|3|87||8|2|3|68||20|5|3|67||36|9|3|67||16|4|3|67||24|6|3|67||32|8|3|67||28|7|3|67||48|12|3|43||44|11|3|43||40|10|3|43||21|5|4|100||17|4|4|100||25|6|4|100||9|2|4|99||13|3|4|99||29|7|4|88||33|8|4|88||41|10|4|87||49|12|4|87||45|11|4|87||5|1|4|66||37|9|4|22|+-----+------------+-----------+-----+#表1：求出每门课程的课程course_id,与最高分数first_numSELECTcourse_id,max(num)first_numFROMscoreGROUPBYcourse_id;+-----------+-----------+|course_id|first_num|+-----------+-----------+|1|91||2|100||3|87||4|100|+-----------+-----------+#表2：去掉最高分，再按照课程分组，取得的最高分，就是第二高的分数second_numSELECTscore.course_id,max(num)second_numFROMscoreINNERJOIN(SELECTcourse_id,max(num)first_numFROMscoreGROUPBYcourse_id)AStONscore.course_id=t.course_idWHEREscore.num<t.first_numGROUPBYcourse_id;+-----------+------------+|course_id|second_num|+-----------+------------+|1|90||2|88||3|68||4|99|+-----------+------------+#将表1和表2联合到一起，得到一张表t3，包含课程course_id与该们课程的first_num与second_numSELECTt1.course_id,t1.first_num,t2.second_numFROM(SELECTcourse_id,max(num)first_numFROMscoreGROUPBYcourse_id)ASt1INNERJOIN(SELECTscore.course_id,max(num)second_numFROMscoreINNERJOIN(SELECTcourse_id,max(num)first_numFROMscoreGROUPBYcourse_id)AStONscore.course_id=t.course_idWHEREscore.num<t.first_numGROUPBYcourse_id)ASt2ONt1.course_id=t2.course_id;+-----------+-----------+------------+|course_id|first_num|second_num|+-----------+-----------+------------+|1|91|90||2|100|88||3|87|68||4|100|99|+-----------+-----------+------------+#查询前两名的学生（有可能出现并列第一或者并列第二的情况）SELECTscore.student_id,t3.course_id,t3.first_num,t3.second_numFROMscoreINNERJOIN(SELECTt1.course_id,t1.first_num,t2.second_numFROM(SELECTcourse_id,max(num)first_numFROMscoreGROUPBYcourse_id)ASt1INNERJOIN(SELECTscore.course_id,max(num)second_numFROMscoreINNERJOIN(SELECTcourse_id,max(num)first_numFROMscoreGROUPBYcourse_id)AStONscore.course_id=t.course_idWHEREscore.num<t.first_numGROUPBYcourse_id)ASt2ONt1.course_id=t2.course_id)ASt3ONscore.course_id=t3.course_idWHEREscore.num>=t3.second_numANDscore.num<=t3.first_num;+------------+-----------+-----------+------------+|student_id|course_id|first_num|second_num|+------------+-----------+-----------+------------+|2|3|87|68||2|4|100|99||3|3|87|68||3|4|100|99||4|4|100|99||5|4|100|99||6|2|100|88||6|4|100|99||7|2|100|88||8|2|100|88||9|1|91|90||9|2|100|88||10|1|91|90||11|1|91|90||12|1|91|90||13|3|87|68|+------------+-----------+-----------+------------+#排序后可以看的明显点SELECTscore.student_id,t3.course_id,t3.first_num,t3.second_numFROMscoreINNERJOIN(SELECTt1.course_id,t1.first_num,t2.second_numFROM(SELECTcourse_id,max(num)first_numFROMscoreGROUPBYcourse_id)ASt1INNERJOIN(SELECTscore.course_id,max(num)second_numFROMscoreINNERJOIN(SELECTcourse_id,max(num)first_numFROMscoreGROUPBYcourse_id)AStONscore.course_id=t.course_idWHEREscore.num<t.first_numGROUPBYcourse_id)ASt2ONt1.course_id=t2.course_id)ASt3ONscore.course_id=t3.course_idWHEREscore.num>=t3.second_numANDscore.num<=t3.first_numORDERBYcourse_id;+------------+-----------+-----------+------------+|student_id|course_id|first_num|second_num|+------------+-----------+-----------+------------+|9|1|91|90||10|1|91|90||11|1|91|90||12|1|91|90||8|2|100|88||9|2|100|88||6|2|100|88||7|2|100|88||2|3|87|68||3|3|87|68||13|3|87|68||2|4|100|99||3|4|100|99||4|4|100|99||5|4|100|99||6|4|100|99|+------------+-----------+-----------+------------+

21、查询不同课程但成绩相同的学号，课程号，成绩

selectdistinctt1.student_id,t1.course_id,t1.numfromscoret1,(selectstudent_id,course_id,numfromscore)t2wheret1.num=t2.numandt1.course_id<>t2.course_idorderbynum;+------------+-----------+-----+|student_id|course_id|num|+------------+-----------+-----+|6|1|9||7|1|9||8|1|9||1|2|9||1|4|66||3|2|66||12|2|77||10|2|77||3|1|77||11|2|77||3|3|87||11|4|87||12|4|87||13|3|87||10|4|87||7|4|88||8|4|88||9|2|88||4|4|100||5|4|100||6|2|100||6|4|100||7|2|100||8|2|100|+------------+-----------+-----+

22、查询没学过“叶平”老师课程的学生姓名以及选修的课程名称；

SELECTstudent.sname,course.cnameFROMstudent,courseWHEREsidNOTIN(SELECTDISTINCTstudent_idFROMscoreWHEREcourse_idIN(SELECTcourse.cidFROMcourseINNERJOINteacherONcourse.teacher_id=teacher.tidWHEREteacher.tname='叶平老师'));+--------+--------+|sname|cname|+--------+--------+|理解|生物||理解|物理||理解|体育||理解|美术||钢蛋|生物||钢蛋|物理||钢蛋|体育||钢蛋|美术||张三|生物||张三|物理||张三|体育||张三|美术||张一|生物||张一|物理||张一|体育||张一|美术||张二|生物||张二|物理||张二|体育||张二|美术||张四|生物||张四|物理||张四|体育||张四|美术||铁锤|生物||铁锤|物理||铁锤|体育||铁锤|美术||李三|生物||李三|物理||李三|体育||李三|美术||李一|生物||李一|物理||李一|体育||李一|美术||李二|生物||李二|物理||李二|体育||李二|美术||李四|生物||李四|物理||李四|体育||李四|美术||如花|生物||如花|物理||如花|体育||如花|美术||刘三|生物||刘三|物理||刘三|体育||刘三|美术||刘一|生物||刘一|物理||刘一|体育||刘一|美术||刘二|生物||刘二|物理||刘二|体育||刘二|美术||刘四|生物||刘四|物理||刘四|体育||刘四|美术|+--------+--------+

23、查询所有选修了学号为1的同学选修过的一门或者多门课程的同学学号和姓名；

SELECTsid,snameFROMstudentWHEREsidin(SELECTDISTINCTstudent_idFROMscoreWHEREcourse_idin(SELECTcourse_idFROMscoreWHEREstudent_id=1));+-----+--------+|sid|sname|+-----+--------+|1|理解||2|钢蛋||3|张三||4|张一||5|张二||6|张四||7|铁锤||8|李三||9|李一||10|李二||11|李四||12|如花|+-----+--------+

24、任课最多的老师中学生单科成绩最高的学生姓名

SELECTsnameFROMstudentWHEREsidIN(SELECTstudent_idFROMscore,(SELECTcourse_id,MAX(num)最大值FROMscoreWHEREcourse_idin(SELECTcidFROMcourseWHEREteacher_id=(SELECTteacher_idFROMcourseGROUPBYteacher_idORDERBYCOUNT(cid)DESCLIMIT1))GROUPBYcourse_idHAVINGmax(num))AWHEREA.最大值=score.numANDscore.course_id=A.course_id);+--------+|sname|+--------+|张一||张二||张四||铁锤||李三|+--------+

上述就是小编为大家分享的如何进行mysql多表查询了，如果刚好有类似的疑惑，不妨参照上述分析进行理解。如果想知道更多相关知识，欢迎关注亿速云行业资讯频道。