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