Check whether field exist in MongoDB or not?

You can use $exists operator for this. Let us first create a collection with documents −

>db.checkFieldExistsDemo.insertOne({"StudentFirstName":"John","StudentGender":"Male","StudentMongoDBScore":89});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5cd909611a844af18acdffbd")
}
>db.checkFieldExistsDemo.insertOne({"StudentFirstName":"Emma","StudentGender":"Female","StudentMongoDBScore":58});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5cd909781a844af18acdffbe")
}
>db.checkFieldExistsDemo.insertOne({"StudentFirstName":"Carol","StudentGender":"Male","StudentMongoDBScore":77});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5cd909871a844af18acdffbf")
}
>db.checkFieldExistsDemo.insertOne({"StudentFirstName":"David","StudentMongoDBScore":98});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5cd909a31a844af18acdffc0")
}

Following is the query to display all documents from a collection with the help of find() method −

> db.checkFieldExistsDemo.find().pretty();

This will produce the following output −

{
   "_id" : ObjectId("5cd909611a844af18acdffbd"),
   "StudentFirstName" : "John",
   "StudentGender" : "Male",
   "StudentMongoDBScore" : 89
}
{
   "_id" : ObjectId("5cd909781a844af18acdffbe"),
   "StudentFirstName" : "Emma",
   "StudentGender" : "Female",
   "StudentMongoDBScore" : 58
}
{
   "_id" : ObjectId("5cd909871a844af18acdffbf"),
   "StudentFirstName" : "Carol",
   "StudentGender" : "Male",
   "StudentMongoDBScore" : 77
}
{
   "_id" : ObjectId("5cd909a31a844af18acdffc0"),
   "StudentFirstName" : "David",
   "StudentMongoDBScore" : 98
}

Following is the query to check whether a field exist in MongoDB −

> db.checkFieldExistsDemo.find({"StudentMongoDBScore":98, "StudentGender":{"$exists": false}},{'StudentFirstName': 1, '_id':0});

This will produce the following output −

{ "StudentFirstName" : "David" }

Nishtha Thakur

Updated on 30-Jul-2019 22:30:26

• Related Questions & Answers
• How can I check whether a field exists or not in MongoDB?
• How to check whether a key exist in JavaScript object or not?
• Select MongoDB documents where a field either does not exist, is null, or is false?
• Check whether IdentityHashMap empty or not in Java?
• Check whether a field is empty or null in MySQL?
• Check whether a NavigableMap empty or not in Java
• How to check whether a particular key exist in javascript object or array?
• JavaScript Check whether string1 ends with strings2 or not
• Check whether a character is Uppercase or not in Java
• Check whether a character is Lowercase or not in Java
• Check whether a Stack is empty or not in Java
• Check whether a HashSet is empty or not in Java
• Check whether the file is hidden or not in Java
• How to check if a field in MongoDB is [] or {}?
• How do I check whether a field contains null value in MongoDB?