mongodb-如何查找然后聚合 [英] mongodb - how to find and then aggregate

问题描述

我有一个包含以下模式文档的集合.我想过滤/查找包含女性性别的所有文档并汇总总分.我尝试了以下语句，它显示了无效的管道错误.

I have collection that contains documents with below schema. I want to filter/find all documents that contain the gender female and aggregate the sum of brainscore. I tried the below statement and it shows a invalid pipeline error.

db['!all'].aggregate({ $and: [ {'GENDER' :  'F'} , {'DOB' : { $gte : 19400801, $lte : 20131231 }} ]  }, { $group : { _id : "$GENDER", totalscore : { $sum : "$BRAINSCORE" } } } )

模式:

{
"_id" : ObjectId("53f63fc8f2b643f6ebb8a1a9"),
"DOB" : 19690112,
"GENDER" : "F",
"BRAINSCORE" : 65
},
{
"_id" : ObjectId("53f63fc8f2b643f6ebb8a1a2"),
"DOB" : 19950116,
"GENDER" : "F",
"BRAINSCORE" : 44
},
{
"_id" : ObjectId("53f63fc8f2b643f6ebb8a902"),
"DOB" : 19430216,
"GENDER" : "M",
"BRAINSCORE" : 71
}

请帮助...

推荐答案

您必须使用 $ match :

db['!all'].aggregate([
  {$match:
    {'GENDER': 'F',
     'DOB':
      { $gte: 19400801,
        $lte: 20131231 } } },
  {$group:
     {_id: "$GENDER",
     totalscore:{ $sum: "$BRAINSCORE"}}}
])

输出:

{ "_id" : "F", "totalscore" : 109 }

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