CODEWITHSUNDEEP
node.jsmongodbaggregation-frameworkaggregation
Rahul Saini
Rahul Saini

Reputation: 937

How to calculate number of unique data in mongoDB

I'm very new beginner in mongoDB.

we have to show output data in which having

  1. Unique number of user by date.

  2. Number of Android user and Ios user.

This is input JSON data

Input

[{
  'name' : 'user1',
  'date' : '23/09/2017',
  'deviceType' : 'Android'
 },
{
 'name' : 'user2',
 'date' : '24/09/2017',
 'deviceType' :'ios'
},
{
'name' : 'user1',
'date' : '23/09/2017',
'deviceType' :'ios'
},
{
'name' : 'user2',
'date' : '23/09/2017',
'deviceType' :'ios'
},
{
'name' : 'user1',
'date' : '24/09/2017',
'deviceType' :'ios'
},
{
'name' : 'user2',
'date' : '25/09/2017',
'deviceType' :'Android'
}   
]

I'm very confused what is query to fetch required data.

And Output is

Output

   [{
    'date' : '23/09/2017',
    'iosCount': 2,
    'androidCount':1
   }, 
  {
   'date' : '24/09/2017',
   'iosCount': 2,
   'androidCount':0
  },
  {
   'date' : '25/09/2017',
  'iosCount': 0,
  'androidCount':1
 }
]

Upvotes: 1

Views: 65

Answers (2)

raghav kumar
raghav kumar

Reputation: 106

@ Buzz Moschetti

If date "23/09/2017" has input data like 

[{'name' : 'user1','date' : '23/09/2017','deviceType' : 'Android'},
 {'name' : 'user1','date' : '23/09/2017','deviceType' :'ios'},
 {'name' : 'user1','date' : '23/09/2017','deviceType' : 'Android'},
 {'name' : 'user2','date': '23/09/2017','deviceType':'ios'}]

output 

[{'date' : 23/09/2017, totalIos : 2, totalAndroid: 1}]

user1 has data 2 android and 1 Ios data. So only 1 android data will be count.

Upvotes: 1

Buzz Moschetti
Buzz Moschetti

Reputation: 7621

Here's one solution, and it is neutral to device types. If you add more, the agg pipeline will adapt to the new values.

db.foo.aggregate([
{$group: {_id: {d:"$date",t:"$deviceType"}, n: {$sum:1}}}
,{$group: {_id: "$_id.d", devices: {$push: {type:"$_id.t", n:"$n"}} }}
                ]);

{
"_id" : "24/09/2017",
"devices" : [
    {
        "type" : "ios",
        "n" : 2
    }
]
{
"_id" : "23/09/2017",
"devices" : [
    {
        "type" : "ios",
        "n" : 2
    },
    {
        "type" : "Android",
        "n" : 1
    }
]
}
{
"_id" : "25/09/2017",
"devices" : [
    {
        "type" : "Android",
        "n" : 1
    }
]
}

If you really want exactly the output you seek:

db.foo.aggregate([
    {$group: {_id: "$date",
        iosCount: {$sum: {$cond: [ {$eq: [ "$deviceType","ios"]}, 1, 0 ] }},
        androidCount: {$sum: {$cond: [ {$eq: ["$deviceType","Android"]}, 1, 0] }}
        }}
                ]);

Upvotes: 1

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