小编Has*_*Bit的帖子

情况是：我有一个存储库和两种方法，其中一种看起来像：

//There is no warning about: Activity domain type or valid projection interface expected here...
@Query("select distinct a.creatorId from Activity a")
Optional<List<String>> findAllCreatorIds();

第二种方法如下所示：

//There i have warning about: Activity domain type or valid projection interface expected here
@Query("select distinct a.creatorId from Activity a join a.categories c where c.name in ?1")
Optional<List<String>> findAllCreatorIdsByCategoryNames(Set<String> categoryNames);

看起来可行，并且通过了测试，并且生成的查询如下：

SELECT DISTINCT activity0_.created_by AS col_0_0_
FROM activities activity0_
INNER JOIN category_item categories1_ ON 
activity0_.id=categories1_.activity_id
INNER JOIN categories category2_ ON 
categories1_.category_id=category2_.id
WHERE category2_.name IN (?)

我进行了更改以使用投影界面。简单的投影界面是： …