棘手的mongodb查询问题:我有一个“帐户”集合，其中包含一堆文档(经过简化并将实际数据交换为非真实值)如下所示:{"_id":"","Roles":{"D7753879C7020F8ECF947122FA211413":{"_id":"","OrgName":"ACME","Rolename":"CoyoteLiaison",},"CFA7722E6799170706E4C5FFF3F01E63":{"_id":"","OrgName":"ACME","Rolename":"MembershipAdmin",},"C7020F8ECF947122FAGIGHFVFF3F7753":