CODEWITHSUNDEEP
mongodbmongodb-query
Anuj More
Anuj More

Reputation: 22101

Get the count of the number of documents in a Collection Mongodb

Is there a way to list all the collection names and the document count for each collection in a single query?

The one that I could find only gives the count for a particular collection. For example, if Users was a collection then

db.Users.count()

Would give me the count of the number of documents in the collection Users.

Upvotes: 9

Views: 8613

Answers (3)

Markus W Mahlberg
Markus W Mahlberg

Reputation: 20712

No, there isn't. You have to use 

var collections = db.runCommand({
  listCollections:1,
  filter:{ name:{ $not: /^system\..*/ } }
})

to get all collections created by the user and iterate over those collections

for (var index = 0; index < collections.length; index++) {
    var current = collections[index];
    var doccount = db.runCommand({collStats:current,scale:1024,verbose:true}).count;
    print(current + ":" + doccount);
}

Upvotes: -1

Laxmikant Dange
Laxmikant Dange

Reputation: 7698

If you just want to print the numbers and count, then you can use forEach.

db.getCollectionNames().forEach(function(colName){
  print(colName+": "+db.collection(colName).count());
});

If you want to use it for any other operations, then you can use map function.

db.getCollectionNames().map(function(colName){
  return {
    "columnName":colName,
    "count":db.getCollection(colName).count()
  }
});

Upvotes: 2

Blakes Seven
Blakes Seven

Reputation: 50426

In the shell all you need to do is this:

db.getCollectionNames().map(function(name) { 
    return { "name": name, "count": db[name].count() } 
})

There is no "command" and there is not "singular" collection query ( it is technically still multiple queries made for each collection, and a "source" query ) to do this since that is not how MongoDB stores the data. But there is a simple programitic method, and this is basically available to all drivers as well.

Upvotes: 11

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