嗨，请帮助我是MongoDB的新手，我有两个收集用户和地址，我想获得所有居住在同一城市的用户
Mongoose方案：
var Person = mongoose.model('Person', {
fname: String,
mname: String,
lname: String,
address: {type: Schema.Types.ObjectId, ref: 'Address'}
});
var Address = mongoose.model('Address', {
houseNum: String,
street: String,
city: String,
state: String,
country: String
});
db.Person.aggregate([
{
$lookup: {
from: "Address",
localField: "address",
foreignField: "_id",
as: "docs"
}
},
{
$group: {
_id: {
$first: "$docs.city"
},
person_ids: {
$push: "$_id"
}
}
}
])
mongoplayground