我现在所拥有的是：
获取所有社区等的List<Town>：
(Town) em.createQuery(from Town towns"
+ " left join fetch towns.neighborhoods neighborhood"
+ " left join fetch neighborhood.population population"
+ " left join fetch population.age age"
+ " where age.value = :ageValue")
.setParameter("ageValue", ageValue)
我想得到一个只有一个邻居的
List<Town>，这是第一个在neighborhood.creationDate的邻居。我怎么做 ？
我不想全部拿走然后将其删除。
谢谢。
最佳答案
我建议在where子句中添加一个子查询，如下所示：
where age.value = :ageValue
AND neighborhood.creationDate =
(Select max(nh.creationDate) From Neighborhood nh
where nh.townsId = towns.townsId)