英文:
How to remove nested field in golang mongodb group aggregation?
问题
我是你的中文翻译助手，以下是翻译好的内容：
我是golang和mongodb的初学者，我在使用mongodb的聚合操作中遇到了一个问题，即如何删除嵌套字段。我刚刚阅读了mongodb的文档，我认为可以使用mongodb的$project操作来删除字段，但是我找不到相关的示例。这是查询的结果：
{"data": [{"_id": "60db0920a2f13ba5037c90f5","email": "jodi@admin.com","is_verified": false,"password": "...","username": "jodi"}],"page": 1,"per_page": 3,"total": 1}
如何删除password字段？对于这段代码，我应该怎么做？
q := c.Query("q")perPage, err := strconv.Atoi(c.Query("per_page"))if err != nil || perPage < 1 {perPage = 10}page, err := strconv.Atoi(c.Query("page"))if err != nil || page < 1 {page = 1}startIndex, err := strconv.Atoi(c.Query("page"))if err != nil || startIndex < 1 {startIndex = 0} else if startIndex > 0 && page < 1 {startIndex = (startIndex * perPage) - perPage} else {startIndex = 0}matchStage := bson.D{{"$match", bson.D{{}}}}if q != "" {matchStage = bson.D{{"$match", bson.D{{"username", q},}},}}groupStage := bson.D{{"$group", bson.D{{"_id", bson.D{{"_id", "null"}}},{"total", bson.D{{"$sum", 1}}},{"data", bson.D{{"$push", "$$ROOT"}}},{"page", bson.D{{"$first", page}}},{"per_page", bson.D{{"$first", perPage}}},}}}projectStage := bson.D{{"$project", bson.D{{"_id", 0},{"total", 1},{"page", 1},{"per_page", 1},{"data", bson.D{{"$slice", []interface{}{"$data", startIndex, perPage}}}},}}}result, err := userCollection.Aggregate(ctx,mongo.Pipeline{matchStage, groupStage, projectStage,},)
希望对你有帮助！如果你有任何其他问题，请随时提问。
英文:
I beginner in golang and mongodb, and I have problem with remove nested field using aggregate group mongodb. I just read the mongodb doc and I think remove field can handle with mongodb $project but I cant find the example to do that. this is the result of query
{"data": [{"_id": "60db0920a2f13ba5037c90f5","email": "jodi@admin.com","is_verified": false,"password": "...","username": "jodi"}],"page": 1,"per_page": 3,"total": 1}
how to remove password field? what should I do with this code?
q := c.Query("q")perPage, err := strconv.Atoi(c.Query("per_page"))if err != nil || perPage < 1 {perPage = 10}page, err := strconv.Atoi(c.Query("page"))if err != nil || page < 1 {page = 1}startIndex, err := strconv.Atoi(c.Query("page"))if err != nil || startIndex < 1 {startIndex = 0} else if startIndex > 0 && page < 1 {startIndex = (startIndex * perPage) - perPage} else {startIndex = 0}matchStage := bson.D{{"$match", bson.D{{}}}}if q != "" {matchStage = bson.D{{"$match", bson.D{{"username", q},}},}}groupStage := bson.D{{"$group", bson.D{{"_id", bson.D{{"_id", "null"}}},{"total", bson.D{{"$sum", 1}}},{"data", bson.D{{"$push", "$$ROOT"}}},{"page", bson.D{{"$first", page}}},{"per_page", bson.D{{"$first", perPage}}},}}}projectStage := bson.D{{"$project", bson.D{{"_id", 0},{"total", 1},{"page", 1},{"per_page", 1},{"data", bson.D{{"$slice", []interface{}{"$data", startIndex, perPage}}}},}}}result, err := userCollection.Aggregate(ctx,mongo.Pipeline{matchStage, groupStage, projectStage,},)
答案1
得分: 0
你可以明确指定你想在 data 中看到的内部文档的字段。
MongoDB文档：$project嵌入文档字段
英文:
You can explicitly specify which fields in inner document you wanna see in data.
Mongo doc: $project embeded document fields
答案2
得分: 0
根据@sirsova的建议，我在mongo.Pipeline中添加了另一个$project，并解决了这个问题。
removeGroupItem := bson.D{{"$project", bson.D{{"data.password", 0},}},}result, err := userCollection.Aggregate(ctx,mongo.Pipeline{matchStage, groupStage, projectStage, removeGroupItem},)
英文:
based on @sirsova suggestion, I add another $project inside mongo.Pipline and solve the problem.
removeGroupItem := bson.D{{"$project", bson.D{{"data.password", 0},}},}result, err := userCollection.Aggregate(ctx,mongo.Pipeline{matchStage, groupStage, projectStage, removeGroupItem},)
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