How to take unique values from mongodb aggregate pipeline

Question

My current mongodb aggregate pipeline output is

[
    {
        "CustomerID":"E001",
        "CustomerName":"Suresh",
        "CustomerPhone":"919889902----",        
    },
    {
        "CustomerID":"E001",
        "CustomerName":"Suresh",
        "CustomerPhone":"919889902----",        
    },
    {
        "CustomerID":"E002",
        "CustomerName":"Ramesh",
        "CustomerPhone":"919889902----",        
    },
    {
        "CustomerID":"E003",
        "CustomerName":"Kishore",
        "CustomerPhone":"919889902----",        
    },
    {
        "CustomerID":"E002",
        "CustomerName":"Ramesh",
        "CustomerPhone":"919889902----",        
    },
    {
        "CustomerID":"E001",
        "CustomerName":"Suresh",
        "CustomerPhone":"919889902----",        
    }
];

Actual response should be unique based on CustomerID

[
    {
        "CustomerID":"E001",
        "CustomerName":"Suresh",
        "CustomerPhone":"919889902----",        
    },
    {
        "CustomerID":"E002",
        "CustomerName":"Ramesh",
        "CustomerPhone":"919889902----",        
    },
    {
        "CustomerID":"E003",
        "CustomerName":"Kishore",
        "CustomerPhone":"919889902----",        
    }
];

I don't know what operator to use to get unique values from aggregate pipeline.

I am using $project, $sort for projection of response and $skip and $limit for pagination

score 1 · Accepted Answer · answered Dec 07 '17 at 13:29

1

group by the value you want :

db.collection.aggregate([
   {
     $group:{
       _id: "$CustomerID",
       CustomerId: {$first:"$CustomerID"},
       CustomerName: {$first: "$CustomerName"},
       CustomerPhone: {$first: "$CustomerPhone"}
    }
  }
]);

I assume that name and phone are the same for the same customer Id, otherwise replace $first with $addToSet in order to get all names and phones

answered Dec 07 '17 at 13:29

Daphoque

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https://stackoverflow.com/questions/50982594 hi can you please answer my question – Ratan Uday Kumar Jun 22 '18 at 10:24
https://stackoverflow.com/questions/50982594/how-to-calculate-rank-from-total-points-in-aggregate-pipeline-for-gaming-applica/50989833#50989833 – Daphoque Jun 22 '18 at 14:10

How to take unique values from mongodb aggregate pipeline

1 Answers1