Created
April 15, 2016 00:40
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A simple example of how to use $lookup in Golang using mgo.
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| package main | |
| import ( | |
| "fmt" | |
| "gopkg.in/mgo.v2" | |
| "gopkg.in/mgo.v2/bson" | |
| ) | |
| func main() { | |
| session, err := mgo.Dial("localhost") | |
| if err != nil { | |
| panic(err) | |
| } | |
| defer session.Close() | |
| // Optional. Switch the session to a monotonic behavior. | |
| session.SetMode(mgo.Monotonic, true) | |
| collection := session.DB("database").C("collection") | |
| pipeline := []bson.M{ | |
| bson.M{"$match": bson.M{"_id": bson.ObjectIdHex("56b9df0c1e930a99cb2c33e9")}}, | |
| bson.M{"$lookup": bson.M{ "from": "localCollection", "localField": "localField", "foreignField": "foreignField", "as": "resultField"}}, | |
| } | |
| pipe := collection.Pipe(pipeline) | |
| resp := []bson.M{} | |
| err = pipe.All(&resp) | |
| if err != nil { | |
| fmt.Println("Errored: %#v \n", err) | |
| } | |
| fmt.Println(resp) | |
| } |
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hey there @sindbach thank you very much for your fast reply!
Unfortunately, I am new to Go and it was pretty hard for me to come with the exact pipeline, so I just wanted to state here for new people that MongoDB Compass has an "Export to Langauge" button which can create the whole exact pipeline.