在此查詢中我得到了錯誤

Question

在此查詢中：

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)";

我收到錯誤消息：

意外令牌：第1行第22列附近的類別[從com.xtr.schoolmanager.domain.facility.library.LibraryBook中選擇BookCategory類別，com.xtr.schoolmanager.domain.facility.library.BookMaster，com.xtr.schoolmanager.domain .facility.library.BookCategory其中（LibraryBook.id = 18 AND LibraryBook.BookMaster.id = BookMaster.id和BookMaster.BookCategory.id = BookCategory.id）]]； 嵌套異常是org.hibernate.hql.internal.ast.QuerySyntaxException：意外令牌：第1行第22列附近的類別[從com.xtr.schoolmanager.domain.facility.library.LibraryBook，com.xtr.schoolmanager中選擇BookCategory類別。 domain.facility.library.BookMaster，com.xtr.schoolmanager.domain.facility.library.BookCategory，其中（LibraryBook.id = 18 AND LibraryBook.BookMaster.id = BookMaster.id和BookMaster.BookCategory.id = BookCategory.id）]

請幫助我獲得正確答案。

Answer 1

這就是問題：

select  BookCategory category

我猜您想從BookCategory表中選擇category列？ 在這種情況下，它應顯示為：

select  BookCategory.category