我有一组类似以下结构的mongodb文档:
{
"_id" : ObjectId("558cd1c4bf46acde47a0d4f6"),
"content" : "That is very good",
"createTime" : NumberLong("1435292100235"),
"deleted" : false,
"parent" : "",
"poiId" : "538318500cf2e33469a2d819",
"poiType" : "event",
"role" : "user",
"threadId" : "e9f800dc3c6dca0b98604bc08ad5ffec17c2aba1",
"thumbsUp" : 0,
"userId" : "53a85640f66cce8abfdb433e5215c8d981d0df86"
}
{
"_id" : ObjectId("558cd375bf46acde47a0d4f7"),
"content" : "That is very good",
"createTime" : NumberLong("1435292533764"),
"deleted" : false,
"parent" : "558cd1c4bf46acde47a0d4f6",
"poiId" : "538318500cf2e33469a2d819",
"poiType" : "event",
"role" : "user",
"threadId" : "e9f800dc3c6dca0b98604bc08ad5ffec17c2aba1",
"thumbsUp" : 0,
"userId" : "53a85640f66cce8abfdb433e5215c8d981d0df86"
}
{
"_id" : ObjectId("558cd380bf46acde47a0d4f8"),
"content" : "That is very good",
"createTime" : NumberLong("1435292544172"),
"deleted" : false,
"parent" : "",
"poiId" : "538318500cf2e33469a2d819",
"poiType" : "event",
"role" : "user",
"threadId" : "cefd5af2429b42b3b97295db53369af6f1e033c8",
"thumbsUp" : 0,
"userId" : "53a85640f66cce8abfdb433e5215c8d981d0df86"
}
{
"_id" : ObjectId("558cd3cfbf46f275306cb661"),
"content" : "\"喲,看上去不错哦\"",
"createTime" : NumberLong("1435292623005"),
"deleted" : false,
"parent" : "",
"poiId" : "538318500cf2e33469a2d819",
"poiType" : "event",
"role" : "user",
"threadId" : "18e453d0e4d42429d1a517c619da0eba4de8bc65",
"thumbsUp" : 0,
"userId" : "53a85640f66cce8abfdb433e5215c8d981d0df86"
}
相对记录将具有相同的threadId
,我希望能够像这样在聚合查询中将它们与threadId
分组:
相对记录将具有相同的threadId
,我希望在聚合查询中按threadId
将它们分组:
{
_id: e9f800dc3c6dca0b98604bc08ad5ffec17c2aba1 //<- this is the `threadId`
record:[
{
"_id" : ObjectId("558cd1c4bf46acde47a0d4f6"),
"content" : "That is very good",
"createTime" : NumberLong("1435292100235"),
"deleted" : false,
"parent" : "",
"poiId" : "538318500cf2e33469a2d819",
"poiType" : "event",
"role" : "user",
"threadId" : "e9f800dc3c6dca0b98604bc08ad5ffec17c2aba1",
"thumbsUp" : 0,
"userId" : "53a85640f66cce8abfdb433e5215c8d981d0df86"
}
{
"_id" : ObjectId("558cd375bf46acde47a0d4f7"),
"content" : "That is very good",
"createTime" : NumberLong("1435292533764"),
"deleted" : false,
"parent" : "558cd1c4bf46acde47a0d4f6",
"poiId" : "538318500cf2e33469a2d819",
"poiType" : "event",
"role" : "user",
"threadId" : "e9f800dc3c6dca0b98604bc08ad5ffec17c2aba1",
"thumbsUp" : 0,
"userId" : "53a85640f66cce8abfdb433e5215c8d981d0df86"
}
],
count: 2
},
{
_id:cefd5af2429b42b3b97295db53369af6f1e033c8
record:[
{
"_id" : ObjectId("558cd1c4bf46acde47a0d4f6"),
"content" : "That is very good",
"createTime" : NumberLong("1435292100235"),
"deleted" : false,
"parent" : "",
"poiId" : "538318500cf2e33469a2d819",
"poiType" : "event",
"role" : "user",
"threadId" : "e9f800dc3c6dca0b98604bc08ad5ffec17c2aba1",
"thumbsUp" : 0,
"userId" : "53a85640f66cce8abfdb433e5215c8d981d0df86"
}
],
count: 1
}
....
到目前为止,我可以编写聚合查询:
db.comment.aggregate([
{"$match":{"poiId":"538318500cf2e33469a2d819"}},
{"$group":{
"_id":"$threadId",
record:{$first:"$$ROOT"}
}
}
])
我对 MongoDB 的聚合机制不是很熟悉,似乎 $first
不太合适,那我该怎么做呢?
"$push"
运算符。 - armnotstrong$match
以查看不唯一的完整记录。 - takanuva15