Syntax error Include all existing fields and add new fields to document in MongoDB?

Include all existing fields and add new fields to document in MongoDB?

You can achieve this with the help of $addFields operator. To understand the concept, let us create a collection with the document. The query to create a collection with a document is as follows −

> db.addFieldDemo.insertOne({"EmployeeId":101,"EmployeeName":"Larry","EmployeeDetails":{
   "EmployeeSalary":65000,"EmployeeCity":"New York","Message":"Hi"}});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5c7f654d8d10a061296a3c44")
}

Display all documents from a collection with the help of find() method. The query is as follows −

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

The following is the output −

{
   "_id" : ObjectId("5c7f654d8d10a061296a3c44"),
   "EmployeeId" : 101,
   "EmployeeName" : "Larry",
   "EmployeeDetails" : {
      "EmployeeSalary" : 65000,
      "EmployeeCity" : "New York",
      "Message" : "Hi"
   }
}

Here is the query to include all existing fields and add new fields to document in MongoDB −

> db.addFieldDemo.aggregate([ { "$addFields": { "EmployeeBasicSalary":"$EmployeeDetails.EmployeeSalary" } } ]).pretty();

The following is the output −

{
   "_id" : ObjectId("5c7f654d8d10a061296a3c44"),
   "EmployeeId" : 101,
   "EmployeeName" : "Larry",
   "EmployeeDetails" : {
      "EmployeeSalary" : 65000,
      "EmployeeCity" : "New York",
      "Message" : "Hi"
   },
   "EmployeeBasicSalary" : 65000
}

Look at the sample output, “EmployeeBasicSalary” has been added.

Updated on: 2019-07-30T22:30:25+05:30

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