Hibernate 的HQL中一个经典函数elements的使用

在传递索引和元素给集合时（elements and indices函数）和传递子查询的结果集时，SQL函数any, some, all, exists, in都是被支持的：

可编写如下Hql 语句完成查询：

HQL代码 select Blog    

 from Blog, Book
 where Blog.author in elements(Book.authors)
     and Book.id=?

对应的Sql近似如下：

Sql代码<embed src="http://www.iteye.com/javascripts/syntaxhighlighter/clipboard_new.swf" width="14" height="15" type="application/x-shockwave-flash"></embed>

select  blog.*
from  blog, book
where  (blog.author  in  ( select  author.authorid
        from  book_author
        where  book.id=book_author.bookid))
    and  book.id=?

项目中统计中使用如下：

摘取其中一部分：

 

if (condition.getHasGym() != null && condition.getHasGym()) {
   sb.append(" and " + AmuseFacilities.FITNESSROOM.getCode() + " in elements(h.hotelInfo.hotelFacilityInfo.amuseFacilities)");
  }