SQL实验2

最新推荐文章于 2024-07-25 22:07:48 发布

浪里小黑狼

最新推荐文章于 2024-07-25 22:07:48 发布

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本文链接：https://blog.youkuaiyun.com/qq_41398448/article/details/80209532

本文精选了一系列实用的SQL查询案例，包括如何查询特定条件的学生信息、课程成绩等，并提供了创建表及插入数据的具体命令，适用于数据库管理和数据分析的学习者。

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查询所在系部为“MA”且选修了高等数学课程的学生姓名，年龄，性别；

select student.sname,sage,ssex
from student,course
where sdept='MA' and cname='数学'

查询选修了数据结构课程，且成绩在90分以上的学生学号；

select distinct SC.sno
from SC
where sc.grade>90 and sc.cno='5'

查询选修了数据结构课程，且成绩在90分以上的学生姓名，年龄；

select distinct sage,sname
from SC,student
where sc.grade>90 and cno='5'
      and student.Sno=sc.Sno

查询选修了数据结构课程的学生学号，姓名，成绩；

select distinct grade,sname,student.Sno
from SC,student
where  cno='5'and student.Sno=sc.Sno

查询所在系部为“MA”的女生人数；

select COUNT(*)
from student
where  Sdept='MA' and Ssex='女'

查询选修了2号课程的学生姓名；

select sname
from student,SC
where  cno='2' and student.sno=sc.sno

查询没有选修2号课程的学生姓名

select Sname
from  student
where not exists
     ( select *
	   from sc
	   where sno=Student.sno and cno='2')

查询选修了全部课程的学生的姓名；

select Sname
from  student
where not exists
     ( select *
	   from Course
	   where  not exists
	             (select *
				  from sc
				   where sno=student.Sno
				          and cno=Course.Cno
						  )
						  )

查询至少选修了学号为“201215121”的学生所选修的全部课程的学生学号和姓名；

select distinct sno
from sc scx
where not exists
         ( select *
		   from sc scy
		   where scy.Sno='201215121' and
		         not exists
				 ( select *
				   from sc scz
				   where scz.sno=scx.sno and
				   scz.Cno=scy.cno
				   )
		  )

查询学生的总人数；

select count(*)
from student

查询每个系部的学生人数；

select sdept,count(sdept)
from student
group by Sdept

查询选修了1号课程的学生人数；

select count(cno)
from SC
where cno='1'

下面附建立表命令

CREATE TABLE Student  
        
      (Sno   CHAR(9) PRIMARY KEY,     
             
  Sname CHAR(20) UNIQUE,        
     
          Ssex    CHAR(2),
     
               Sage   SMALLINT,
  
               Sdept  CHAR(20)
); 
  
  
insert into student values('201215121','李勇','男',20,'CS');
insert into student values('201215122','刘晨','女',19,'CS');
insert into student values('201215123','王敏','女',18,'MA');
insert into student values('201215125','张立','男',19,'IS');
insert into student values('201215126','李一平','男',18,'IS');
insert into student values('201215127','张琴','女',19,'CS');
insert into student values('201215128','王方','女',20,'MA');
insert into student values('201215129','黄林林','男',21,'IS');

CREATE TABLE  Course 
         (Cno   CHAR(4) PRIMARY KEY, 
       	 Cname  CHAR(40),    
   
    	 Cpno     CHAR(4), 
     
    Ccredit  SMALLINT,
 
          ); 

insert into course values('1','数据库','5',4);
insert into course values('2','数学',null,2);
insert into course values('3','信息系统','1',4);
insert into course values('4','操作系统','6',3);
insert into course values('5','数据结构','7',4);
insert into course values('6','数据处理',null,2);
insert into course values('7','C语言','6',4);


CREATE TABLE  SC 
         (Sno  CHAR(9),
 
         Cno  CHAR(4),  
          Grade  SMALLINT, 
           PRIMARY KEY (Sno,Cno))

insert into sc values('201215121','1',92); 
insert into sc values('201215121','2',85); 
insert into sc values('201215121','3',88); 
insert into sc values('201215121','4',98); 
insert into sc values('201215121','5',89); 
insert into sc values('201215121','6',95); 
insert into sc values('201215121','7',93); 
insert into sc values('201215122','2',90); 
insert into sc values('201215122','3',80); 
insert into sc values('201215122','4',85); 
insert into sc values('201215122','6',92); 
insert into sc values('201215123','1',90); 
insert into sc values('201215123','2',84); 
insert into sc values('201215123','3',91); 
insert into sc values('201215123','4',90); 
insert into sc values('201215123','5',80); 
insert into sc values('201215123','6',78); 
insert into sc values('201215123','7',65); 
insert into sc values('201215128','1',78); 
insert into sc values('201215128','2',82); 
insert into sc values('201215128','3',77); 
insert into sc values('201215128','4',79); 
insert into sc values('201215128','5',92); 
insert into sc values('201215128','6',98); 
insert into sc values('201215128','7',50); 
insert into sc values('201215125','1',67); 
insert into sc values('201215125','2',71); 
insert into sc values('201215125','3',90); 
insert into sc values('201215126','4',81); 
insert into sc values('201215126','5',90); 
insert into sc values('201215126','6',56); 
insert into sc values('201215126','7',89); 
insert into sc values('201215127','1',81); 
insert into sc values('201215127','2',72); 
insert into sc values('201215127','3',90); 
insert into sc values('201215127','4',64); 
insert into sc values('201215127','5',79); 
insert into sc values('201215127','6',50); 
insert into sc values('201215127','7',96);

SC表

Course表

Student表