学说为每个主人获取最新的细节

Question

我有像这样的QueryBuilder

$query = $this->getEntityManager()
  ->createQueryBuilder()
  ->select('partial master.{id,name}, partial detail.{id,name}')
  ->from('AppBundle:Master', 'master')
  ->leftJoin('master.detail', 'detail')
  ->orderBy('detail.id','DESC')
  ->getQuery();
return $query->getArrayResult();

主关系是OneTomany，细节关系很多。我试图获取具有详细信息ID的单一细节更高或更低。哪种QueryBuilder可以实现这一目标？示例我有这样的数据：

1.A, 1.B, 1.C, 2.A, 3.A, 3.C

我想要这样的结果

1.A, 2.A, 3.A

Answer 1

$query = $this->getEntityManager()
    ->createQueryBuilder()
    ->select('master.id, master.name, detail.id, detail.name')
    ->from('AppBundle:Master', 'master')
    ->leftJoin('master.detail', 'detail')
    ->groupBy('master.id')
    ->orderBy('detail.id','DESC')
    ->getQuery()
;
return $query->getArrayResult();

Answer 2

获取您使用的每个主行的最新细节

SELECT m,a 
FROM AppBundleEntityMaster m
    LEFT JOIN m.detail a
    LEFT JOIN AppBundleEntityDetail b 
    WITH a.master = b.master 
    AND a.id < b.id
WHERE b.id IS NULL