一些习题，有助于加深SQL查询。 Relational algebra and SQL Query Consider the following schema of a company database: Employees(eid, ename, address, supereid) Departments(did, dname) Projects(pid, pname, did) Works_on(eid, pid, hours) (1)For each employee, find hi
6、
学生：Student、班级：Class
(1)
GRANT ALL PRIVILEGES
ON Student,Class
TO U1
WITH GRANT OPTION
(2)
GRANT UPDATE(address),SELECT
ON Student
TO U2
(3)
GRANT SELECT
ON CLASS
TO PUBLIC
(4)
GRANT UPDATE,SELECT
ON Student
TO R1
(5)
标准SQL：
GRANT R1
TO U1
WITH
