java - 左加入 hql 中的第一场比赛

Question

select 
    schedulingpool.id,
    schedulingpool.allocationVersion,
    schedulingpool.tx.statusId,
    schedulingpool.name,
    schedulingpool.description,
    schedulingpool.schedulingPoolAddresses.name,
    schedulingpool.schedulingPoolAddresses.zip,
    schedulingpool.schedulingPoolAddresses.city,
    schedulingpool.schedulingPoolAddresses.countryId,
    schedulingpool.schedulingPoolAddresses.street,
    schedulingpool.statusId,
    schedulingpool.tx.name,
    schedulingpool.note1,
    schedulingpool.note2
from 
    com.xx.module.mm.jpa.SchedulingPool as schedulingpool 
left join schedulingpool.tx
left join schedulingpool.schedulingPoolAddresses
where schedulingpool.clientId = :clientId
     order by schedulingpool.id DESC

javax.servlet.ServletException: java.lang.IllegalArgumentException: org.hibernate.QueryException: illegal attempt to dereference collection [scheduling0_.id.schedulingPoolAddresses] with element property reference [name]

调度池可以有多个地址，当我执行该语句时，我收到异常。 有没有办法只获取第一个匹配的地址并将其加入以防止出现此异常？

Answer 1

您需要使用别名

select 
    schedulingpool.id,
    schedulingpool.allocationVersion,
    tx.statusId,
    schedulingpool.name,
    schedulingpool.description,
    schedulingPoolAddresses.name,
    schedulingPoolAddresses.zip,
    schedulingPoolAddresses.city,
    schedulingPoolAddresses.countryId,
    schedulingPoolAddresses.street,
    schedulingpool.statusId,
    tx.name,
    schedulingpool.note1,
    schedulingpool.note2
from 
    com.xx.module.mm.jpa.SchedulingPool as schedulingpool 
left join schedulingpool.tx tx
left join schedulingpool.schedulingPoolAddresses schedulingPoolAddresses
where schedulingpool.clientId = :clientId
     order by schedulingpool.id DESC

并且您需要在 SchedulingPool 类中将 schedulingPoolAddresses 和 tx 关联起来。