JavaMadeSoEasy.com (JMSE): count() Method - Find count of all employee in collection in MongoDB

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Contents of page >

1) First let's create insert documents in collection in MongoDB
2) Find count of all employee in collection in MongoDB >

2.1) W e will use count() method to find count of all employee in collection in MongoDB.
2.2) Sql query equivalent to above MongoDB query is >

3) Find count of all employee where salary >= 2000 in collection in MongoDB >

3.1) We will use find() and count() methods.
3.2) We can also use $count() operator to find count of all employee where salary >= 2000 in collection in MongoDB.
3.3) Sql query equivalent to above MongoDB query is >

4) Summary -

count() method in Mongodb>

count() method to find count of documents in collection in MongoDB.

1) First let's create insert documents in collection in MongoDB

1.1) First, Let's create new collection and insert document >

db.employee.insert({_id : 1, firstName:"ank", salary : 1000 })

db.employee.insert({_id : 2, firstName:"ank", salary : 2000 })

db.employee.insert({_id : 3, firstName:"sag", salary : 3000 })

db.employee.insert({_id : 4, firstName:"sag", salary : 4000 })

db.employee.insert({_id : 5, firstName:"neh", salary : 5000 })

Above will create collection (or table) (if collection already exists it will insert documents in it).

1.2) FIND > Query all documents of collection using find() method>

db.employee.find()

Output>

{ "_id" : 1, "firstName" : "ank", "salary" : 1000 }

{ "_id" : 2, "firstName" : "ank", "salary" : 2000 }

{ "_id" : 3, "firstName" : "sag", "salary" : 3000 }

{ "_id" : 4, "firstName" : "sag", "salary" : 4000 }

{ "_id" : 5, "firstName" : "neh", "salary" : 5000 }

2) Find count of all employee in collection in MongoDB >

2.1) We will use count() method to find count of all employee in collection in MongoDB.

db.employee.count()

Output >

2.2) Sql query equivalent to above MongoDB query is >

select count(*) from employee;

3) Find count of all employee where salary >= 2000 in collection in MongoDB >

3.1) We will use find() and count() methods.

db.employee.find( { salary : {$gte : 2000} } ).count()

Output >

3.2) We can also use $count() operator to find count of all employee where salary >= 2000 in collection in MongoDB.

Note : $count can be used in MongoDB 3.4 or above.

db.employee.aggregate(
[
   {
     $match: {
       salary : {
         $gte: 2000
       }
     }
   },
   {
     $count: "firstName"
   }
]
)

Output >

3.3) Sql query equivalent to above MongoDB query is >

select count(*) from employee where salary >= 2000

4) Summary -

So in this MongoDB tutorial we learned how to use count() Method - How to find count of all employee in collection in MongoDB

count of all employee in collection in MongoDB.

db.employee.count()

Find count of all employee where salary >= 2000 in collection in MongoDB >

db.employee.find( { salary : {$gte : 2000} } ).count()

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