Mongo：组合并推送超过1个元素

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问题描述

我有一个mongodb收集数据，如下所示；我想根据EmployeedID（即0001）对Speciality，Code和Age字段进行分组。

I have a mongodb collection data as per below;I want to group Speciality,Code and Age fields based on EmployeedID( i.e 0001).

{
"_id" : ObjectId("54d0512191a4da7736e9db43"),
"EmployeeID" : "0001",
"Speciality" : "xxx",
"Code" : "P",
"Age" : 8
}

/* 1 */
{
"_id" : ObjectId("54d0512191a4da7736e9db44"),
"EmployeeID" : "0002",
"Speciality" : "yyyyy",
"Code" : "P",
"Age" : 6
}

/* 2 */
{
"_id" : ObjectId("54d0512191a4da7736e9db45"),
"EmployeeID" : "0001",
"Speciality" : "zzz",
"Code" : "P",
"Age" : 5
}

我已经可以使用以下方式将一个字段（即，基于EmployeeID的Specialty）分组（按数组）。但是，我不确定如何在查询中添加其他字段，例如代码和年龄？

I can already group one field i.e Speciality based on EmployeeID using the way below (push an array). However I am not sure how can I add another fields such as Code and Age into the query?

collection.aggregate([{
    $match: {
        EmployeeID: '0001'
    }
}, {
    "$group": {
        "_id": "$EmployeeID",
        "speciality": {
            "$push": "$Speciality"
        }
    }
}], (function(err, docComp) {

      console.log("JSON.stringify" + JSON.stringify(docComp));

    }
}));

推荐答案

您可以将其汇总为：

collection.aggregate([
{$match:{"EmployeeId":1000}},
{$group:{"_id":"$EmployeeID",
            "speciality":{$push:"$Speciality"},
            "Code":{$push:"$Code"},
            "Age":{$push:"$Age"}}}
])

或者，

collection.aggregate([
{$match:{"EmployeeId":1000}},
{$group:{"_id":"$EmployeeID",
            "data":{$push:{"Speciality":"$Speciality",
                           "Code":"$Code",
                           "Age":"$Age"}}}}
])

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