SQL句比
各位，忙~~ 下面句有什差呢？可以出“句一”等的表式？。
句一：
SELECT DISTINCT CNAME
FROM COURSES C WHERE '男 '=all (select sex from enrolls,students where enrolls.sno=students.sno and enrolls.cno=C.cno)

句二：
select distinct cname from courses,students,enrolls where students.sno=enrolls.sno and courses.cno=enrolls.cno and students.sex= '男 '

[解决办法]
-------- =all -------
SELECT DISTINCT CNAME
FROM COURSES C WHERE '男 ' in (select sex from enrolls,students where enrolls.sno=students.sno and enrolls.cno=C.cno)
[解决办法]
就是ALL的使用区别