在此查询中，我收到错误

Question

在此查询中：

String sql="select  BookCategory category from LibraryBook,BookMaster,BookCategory where (LibraryBook.id="+bookid+" AND LibraryBook.BookMaster.id=BookMaster.id AND BookMaster.BookCategory.id=BookCategory.id)";

我收到错误：

  

意外标记：第1行第22列附近的类别[从com.xtr.schoolmanager.domain.facility.library.LibraryBook，com.xtr.schoolmanager.domain.facility.library.BookMaster，com.xtr中选择BookCategory类别。 schoolmanager.domain.facility.library.BookCategory where（LibraryBook.id = 18 AND LibraryBook.BookMaster.id = BookMaster.id AND BookMaster.BookCategory.id = BookCategory.id）];嵌套异常是org.hibernate.hql.internal.ast.QuerySyntaxException：意外标记：第1行第22列附近的类别[从com.xtr.schoolmanager.domain.facility.library.LibraryBook，com.xtr.schoolmanager中选择BookCategory类别。 domain.facility.library.BookMaster，com.xtr.schoolmanager.domain.facility.library.BookCategory where（LibraryBook.id = 18 AND LibraryBook.BookMaster.id = BookMaster.id AND BookMaster.BookCategory.id = BookCategory.id）]

请帮助我为此得到正确的答案。

Answer 1

这是问题所在：

select  BookCategory category

我猜你要从category表中选择BookCategory列？在这种情况下，它应该是：

select  BookCategory.category