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mongodbgounmarshallingmgo

Golang mgo result into simple slice

I'm fairly new to both Go and MongoDB. Trying to select a single field from the DB and save it in an int slice without any avail.

userIDs := []int64{}

coll.Find(bson.M{"isdeleted": false}).Select(bson.M{"userid": 1}).All(&userIDs)

The above prints out an empty slice. However, if I create a struct with a single ID field that is int64 with marshalling then it works fine.

All I am trying to do is work with a simple slice containing IDs that I need instead of a struct with a single field. All help is appreciated.

Solution

  • Because mgo queries return documents, a few lines of code is required to accomplish the goal:

    var result []struct{ UserID int64 `bson:"userid"` }
err := coll.Find(bson.M{"isdeleted": false}).Select(bson.M{"userid": 1}).All(&result)
if err != nil {
    // handle error
}
userIDs := make([]int64, len(result))
for i := range result {
    userIDs[i] = result.UserID
}