

数据如图,如果我只想获取
{
"companyId" : "QY-20160920-000001",
"accountId" : "57faeeada514b3a2210c4bb5",
"createdAt" : ISODate("2016-10-19T03:57:09.241Z"),
"classify" : "供应",
"deletedAt" : ISODate("2016-10-19T06:06:42.402Z")
}
这一条数据。就是relations下"classify"为"供应"的数据,该怎么获取