MongoDB playground All In One

MongoDB playground All In One

MongoDB REPL

https://mongoplayground.net/

db={
  "teacher": [
    {
      "_id": ObjectId("64fee9b54273ac2234441225"),
      "teacherid": ObjectId("64f1d72a4331bc8fc4c5930f"),
      "name": "xgqfrms"
    }
  ],
  "users": [
    {
      _id: ObjectId("64f1d72a4331bc8fc4c5930f"),
      name: "eric"
    }
  ]
}

aggregate

db.teacher.aggregate([
  {
    $match: {
      "teacherid": ObjectId("64f1d72a4331bc8fc4c5930f")
    }
  },
  {
    $lookup: {
      from: "users",
      localField: "teacherid",
      foreignField: "_id",
      as: "student"
    }
  },
  {
    $unset: "name"
  }
])
// ]).explain()
// ]).pretty()
// Unsupported method: only find(), aggregate(), update() and explain() are supported

demos

mongo

$ mongo

# replace the `YOUR_DATABASE_NAME` with your real database name.
> use YOUR_DATABASE_NAME

# update Teacher collection ✅
> db.Teacher.update(
  {"teacherid" : "64f1d72a4331bc8fc4c5930f"},
  {
    $set: {"teacherid" : ObjectId("64f1d72a4331bc8fc4c5930f")}
  });

> db.Teacher.aggregate([
    {
        $match: {
            "teacherid": ObjectId("64f1d72a4331bc8fc4c5930f")
        }
    },
    {
        $lookup: {
            from: "user",
            localField: "teacherid",
            foreignField: "_id",
            as: "student"
        }
    },
    {
        $unset: "name"
    }
]).pretty();

Node.js

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MongoDB 跨表查询

https://www.cnblogs.com/xgqfrms/p/17724984.html#5215297

refs

https://stackoverflow.com/questions/77193151/how-to-get-data-from-another-collection-in-mongodb/77194045#77194045

https://www.cnblogs.com/xgqfrms/p/17724984.html#5215324

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