要查看用户集合中的哪些文档具有指向特定用户的链接,我使用以下聚合查询:
db.getCollection("users").aggregate([
{
$match: {
$or: [
{_id: ObjectId("5b63133c45a56952c9430776")},
{_id: ObjectId("5b69caec45a56952c8010bdb")},
{_id: ObjectId("5bb49ece45a5696eb624c4f4")}
]
}
},
{
$unwind: {path: "$network"}
},
{
$project: {_id:1,network:1}
},
{
$match:
{"network.id": "5c958c7745a5691cff06f252"}
}
])
给出以下结果,表明三个用户中只有一个匹配:
/* 1 */
{
"_id" : ObjectId("5b69caec45a56952c8010bdb"),
"network" : {
"id" : "5c958c7745a5691cff06f252",
"status" : "connected",
"updated_at" : ISODate("2019-06-27T00:58:45.501Z")
}
}
但是,如果我分别查询三个用户,例如第一个用户:
db.getCollection("users").find({_id:ObjectId("5b63133c45a56952c9430776")}, {network:1});
发现一个网络项未显示在聚合查询中(请参阅项113):
/* 1 */
{
"_id" : ObjectId("5b63133c45a56952c9430776"),
"network" : {
"0" : {
"id" : "5b61b7c845a56960683cc53c",
"status" : "connected",
"updated_at" : ISODate("2019-06-26T03:48:38.293Z")
},
"1" : {
"id" : "5bc7ee7745a56931124e50de",
"status" : "sent"
},
...
"113" : {
"id" : "5c958c7745a5691cff06f252",
"status" : "connected",
"updated_at" : ISODate("2019-06-28T07:19:34.463Z")
},
...
}
}
我的聚合查询是否错误,或者这是聚合框架中的错误?
MongoDB版本3.6.6
答案 0 :(得分:0)
哦,亲爱的。问题在于网元格式不一致。在某些文档中,网络元素可能是未缠绕的,因为它是一个数组:
"network": [
{
"id": "5c958c7745a5691cff06f252",
"status": "connected"
},
{
"id": "5bc7ee7745a56931124e50de",
"status": "sent"
}
]
在其他情况下,$ unwind指令什么也不做,因为格式是键对象:
"network" : {
"0" : {
"id" : "5b61b7c845a56960683cc53c",
"status" : "connected",
"updated_at" : ISODate("2019-06-26T03:48:38.293Z")
},
"1" : {
"id" : "5bc7ee7745a56931124e50de",
"status" : "sent"
}
}
因此,在整个集合中正常发送格式后,一切都按预期工作。 :facepalm: