英文:
How to return multiple values using Go Mongo Distinct
问题
我想从集合中返回值，其中一个是批次（batch），它应该与特定的过滤器不同，即value="Nice"，另一个是vendor。我无法获取vendor的值。
如何使用Distinct实现这一点？我需要使用Find()吗？
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)
英文:
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)
答案1
得分: 1
在Prasad的评论后，我用以下解决方案解决了我的问题。
type Example struct {}var exm []Examplectx, cancel := context.WithTimeout(context.Background(), 30*time.Second)defer cancel()pipeline := []bson.M{{"$match": bson.M{"status": "Pending"}},{"$group": bson.M{"_id": "$batch"}},}cursor, err := db.Collection("xyzcollection").Aggregate(ctx, pipeline)if err != nil {return []Example{}, errors.New(fmt.Sprintf("无法检索数据：%s", err.Error()))}var result Examplefor cursor.Next(ctx) {cursor.Decode(&result)exm = append(exm, result)}return exm, nil
英文:
After prasad comment I have solved my problem with this solution.
type Example struct {}var exm []Examplectx, cancel := context.WithTimeout(context.Background(), 30*time.Second)defer cancel()pipeline := []bson.M{{"$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 Examplefor cursor.Next(ctx) {cursor.Decode(&result)exm = append(exm, result)}return exm, nil
答案2
得分: -1
我找到了一个类似的问题，
你需要使用db.collection.aggregate查询。请在MongoDB文档中阅读相关内容。
英文:
I found a similar question,
You have to use db.collection.aggregate query. Please read it on MongoDB docs
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