我正在尝试了解 Mongo 的整个聚合框架。我是这里的新手。
I have the following documents:
{ "col1": "camera", "fps": 1, "lat": 3 },
{ "col1": "camera", "fps": 3, "lat": 2 }
{ "col1": "recorders", "fps": 9, "lat": 7 }
{ "col1": "cell", "fps": 8, "lat": 1 }
{ "col1": "cell", "fps": 4, "lat": 3 }
我如何设置才能返回结果:
{ "col1": "camera", "fps": 4, "lat": 5 },
{ "col1": "recorders", "fps": 9, "lat": 7 },
{ "col1": "cell", "fps": 12, "lat": 4 },
谢谢
最佳答案
db.yourCollection.aggregate(
{ $group : {
_id : "$col1",
fps : { $sum : "$fps" },
lat : { $sum : "$lat" }
}}
);
看看这个! http://docs.mongodb.org/manual/reference/operator/aggregation/group/
关于mongodb - 带总和的聚合/分组,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/19715284/