数据库 SQL 关系代数 查询语句
student( sid, name, age, gender, department)
course(cno, name, credit, teacher)
register( sid, cno, semester)
用关系代数 写出下面查询。
a. Find the names of students from “qq” department who registered a course taught by “bb”
找出所有来自qq系并注册了一个bb教授的课程 的学生。
b. Find the names of students who registered all courses taught by “bb”
找出这样的学生：注册所有bb教的课程
[解决办法]
关系代码的符号打不出来，
PI s.depart='qq' & teacher='bb' (student X course X register)
QQ群 48866293 / 12035577 / 7440532 / 13666209
http://forum.csdn.net/BList/OtherDatabase .
http://www.accessbbs.cn/bbs/index.php .
http://www.accessoft.com/bbs/index.asp .
http://www.access-programmers.co.uk/forums .
http://www.office-cn.net .
.
http://www.office-cn.net/home/space.php?uid=141646 .
