Symfony2联合查询实现方法

Acme/MspadminBundle/Entity/MspArticle: type: entity table: msp_article manyToOne:  Channel:   targetEntity: MspChannel   inversedBy: Articles   joinColumn:    name: channel_id    referencedColumnName: channel_id  User:   targetEntity: MspUser   inversedBy: Userone   joinColumn:    name: user_id    referencedColumnName: user_id

Acme/MspadminBundle/Entity/MspChannel: type: entity table: msp_channel oneToMany:   Articles:    targetEntity: MspArticle    mappedBy: Channel

Acme/MspadminBundle/Entity/MspUser: type: entity table: msp_user oneToMany:   Userone:    targetEntity: MspArticle    mappedBy: User

$sql="SELECT a.id,a.checkStatus,a.title,a.releaseSysDate,          a.visitTotal,u.userName ,n.name FROM AcmeMspadminBundle:MspArticle a          JOIN a.User u JOIN a.Channel n";$query = $emt->createQuery($sql." Where a.checkStatus = 0 ");$mspArtile = $query->getResult();