在 MongoDB 中查找重复记录 [英] Find duplicate records in MongoDB

问题描述

如何在 mongo 集合中找到重复的字段.

How would I find duplicate fields in a mongo collection.

我想检查是否有任何名称"字段重复.

I'd like to check if any of the "name" fields are duplicates.

{
    "name" : "ksqn291",
    "__v" : 0,
    "_id" : ObjectId("540f346c3e7fc1054ffa7086"),
    "channel" : "Sales"
}

非常感谢！

推荐答案

在 name 上使用聚合并得到 name with count >1:

Use aggregation on name and get name with count > 1:

db.collection.aggregate([
    {"$group" : { "_id": "$name", "count": { "$sum": 1 } } },
    {"$match": {"_id" :{ "$ne" : null } , "count" : {"$gt": 1} } }, 
    {"$project": {"name" : "$_id", "_id" : 0} }
]);

按照重复次数从多到少对结果进行排序:

To sort the results by most to least duplicates:

db.collection.aggregate([
    {"$group" : { "_id": "$name", "count": { "$sum": 1 } } },
    {"$match": {"_id" :{ "$ne" : null } , "count" : {"$gt": 1} } }, 
    {"$sort": {"count" : -1} },
    {"$project": {"name" : "$_id", "_id" : 0} }     
]);

要与name"以外的其他列名称一起使用，请更改$name"；到$column_name"

To use with another column name than "name", change "$name" to "$column_name"

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