如何使用 mongoose 从 mongodb 中的多个集合中获取数据？

Question

我在 mongoDB 中有 3 个集合，结构如下

用户：

"name":""
"email":""
"phone":""
"city":""
"customerID":""

船只：

"address":""
"city":""
"pincode":""
"porderID":""
"customerID":""

订单：

"productName":""
"quantity":""
"pricing":""
"mrp":""
"porderID":""
"customerID":""

如何编写 returns 像这样 json 中所有客户 ID 的获取请求或聚合函数？

[{

customerID:"",
BuyOrder:[{
porderID:"",
productName:"",
quantity:""
ShipmentDetail:[
address:""
city:""
pincode:""
]
}],

customerID:"",
BuyOrder:[{
porderID:"",
productName:"",
quantity:""
ShipmentDetail:[
address:""
city:""
pincode:""
]
}],

}]

任何建议都会有所帮助。

Answer 1

不太清楚你想要什么...没有 input/output 示例，没有有效的 JSON... 并不容易，但我认为你正在寻找这样的东西：

此查询是一个嵌套的 $lookup，其中每个用户使用 customerID 与 orders 加入集合，并且订单与 ships 使用 customerID 也是。

db.users.aggregate([
  {
    "$lookup": {
      "from": "orders",
      "localField": "customerID",
      "foreignField": "customerID",
      "as": "BuyOrder",
      "pipeline": [
        {
          "$lookup": {
            "from": "ships",
            "localField": "customerID",
            "foreignField": "customerID",
            "as": "ShipmentDetail"
          }
        }
      ]
    }
  },
  
])

示例here

您还可以添加一个 $project 阶段以仅输出您想要的字段，例如 this example 结果为：

[
  {
    "BuyOrder": [
      {
        "ShipmentDetail": [
          {
            "address": "",
            "city": "",
            "pincode": ""
          }
        ],
        "porderID": "",
        "pricing": "",
        "productName": "",
        "quantity": ""
      }
    ],
    "customerID": ""
  }
]

如何使用 mongoose 从 mongodb 中的多个集合中获取数据？

How to get data from multiple collections in mongodb using mongoose?

javascript

json

mongoose

mongodb

aggregation-framework