~~~ //users { name:"chengchao",name_id:1, name:"jiangwei",name_id:2 } ~~~ ~~~ //details {school:"武大",detail_id:1}, {school:"华科",detail_id:2} ~~~ 对details遍历,当detail_id等于users的name_id时,让detail对应id的document作为users对应id的属性 ~~~ const MongoClient = require('mongodb').MongoClient; var url = 'mongodb://localhost:27017/'; MongoClient.connect(url, { useNewUrlParser: true }, (err, client) => { if (err) throw err; var test = client.db('test'); test.collection('user').aggregate([ { $lookup: { from: 'detail', localField: 'name_id', foreignField: 'detail_id', as: 'details' } } ]).toArray((err,result)=>{ if(err) throw err; console.log(JSON.stringify(result)); client.close() }) }) ~~~