如何在猫鼬中使用 match 和 groupby？

Posted 2023-03-11

【中文标题】如何在猫鼬中使用 match 和 groupby？

【英文标题】：How to use match and groupby in mongoose?

【发布时间】：2021-07-29 21:33:13

【问题描述】：

我有一个这样的 customerDocument 架构：

const customerDocumentSchema = new mongoose.Schema(
  
    title:  type: String, required: true ,
    section:  type: String ,
    description:  type: String, required: true ,
    customer:  type: mongoose.Schema.Types.ObjectId ,
    documentKey:  type: String ,
  ,
   timestamps: true 
);

我需要根据section 对返回结果进行分组，如下所示：

[
  section1:[title:'',description:'',customer:'',documentKey:'',,...],
  section2:[title:'',description:'',customer:'',documentKey:'',,....],
  sectionN:[....]
]

sections 只是不同的字符串，结果也应该用 customer 过滤，这是一个猫鼬 ID。我应该如何实现这个？

【参考方案1】：

$match您需要的条件 $group by section 并构造 customers 的数组 $group by null 并以键值格式构造部分数组 $arrayToObject 将sections 的键值数组转换为对象 $replaceRoot 将上面转换的对象替换为根

let customer_id = mongoose.Types.ObjectId(customer);
let result = await SchemaModelName.aggregate([
   $match:  customer: 1  ,
  
    $group: 
      _id: "$section",
      customers:  $push: "$$ROOT" 
    
  ,
  
    $group: 
      _id: null,
      sections:  $push:  k: "$_id", v: "$customers"  
    
  ,
   $replaceRoot:  newRoot:  $arrayToObject: "$sections"   
])

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