How to return multiple values using Go Mongo Distinct-CodePudding

I want to return values from collection one is batch which should be distinct with specific filter i.e value="Nice" and another is vendor. I am unable to get vendor values?

How to achieve this using Distinct, Do I have to use Find()?

    ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
    defer cancel()

    filter := bson.D{{Key: "batch", Value: ""}}

    values, err := db.Collection("xyzcollection").Distinct(ctx, "batch", filter)
    if err != nil {
        return nil, err
    }

    batch := make([]string, len(values))
    for i, v := range values {
        batch[i] = v.(string)
    }

    fmt.Println(batch)

CodePudding user response：

I found a similar question,

You have to use db.collection.aggregate query. Please read it on MongoDB docs

Check this out

CodePudding user response：

After prasad comment I have solved my problem with this solution.

    type Example struct {}

    var exm []Example
    ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
    defer cancel()

    pipeline := []bson.M{
        {"$match": bson.M{"status": "Pending"}},
        {"$group": bson.M{"_id": "$batch"}},
    }

    cursor, err := db.Collection("xyzcollection").Aggregate(ctx, pipeline)
    if err != nil {
        return []Example{}, errors.New(fmt.Sprintf("unable to retrive data: %s ", err.Error()))
    }

    var result Example
    for cursor.Next(ctx) {
        cursor.Decode(&result)
        exm = append(exm, result)
    }
    return exm, nil