请看下表:
Books
------
BookId
BookName
AuthorId
SubjectId
PopularityRating(the popularity of the book on a scale of 1 to 10)
Language(such as French, English, German etc)
/////////////////////////
Subjects
---------
SubjectId
Subject(such as History, Geography, Mathematics etc)
/////////////////////////
Authors
--------
AuthorId
AuthorName
Country
哪项查询可以确定就两个以上主题撰写书籍的作者人数？( )
select AuthorName from Authors where Authorid in(select Authorid from Books group by SubjectId having count(*)>1)
select AuthorName from Authors where BookId in(select BookId from Books group by BookId having count(*)>1)
select AuthorName from Authors where Authorid in(select Authorid from Books group by SubjectId,Authorid having count(*)>1)
select AuthorName from Authors where Authorid in(select Authorid from Books group by Authorid having count(*)>1)
None of the above
