How to search in array of object in MongoDB?

To search the array of object in MongoDB, you can use $elemMatch operator. This operator allows us to search for more than one component from an array object.

To understand the above concept, let us create a collection with the document. The query to create a collection with a document is as follows ?

> db.searchArrayDemo.insertOne({"EmployeeFirstName":"Adam","EmployeeLastName":"Smith","EmployeeDateOfBirth":new ISODate("1992-01-31 13:45:10"),    ... "EmployeeSkills":["Spring and Hibernate Framework","Machine Learning"],    ... "EmployeeDetails":[       ... {          ... "EmployeePerformanceArea":"Java",          ... "Year":2001       ... },       ... {       ... "EmployeePerformanceArea":"Python",          ... "Year":2005       ... }    ... ] ... } ... ); {    "acknowledged" : true,    "insertedId" : ObjectId("5c77b3812386c62d05142a6a") } > db.searchArrayDemo.insertOne({"EmployeeFirstName":"Carol","EmployeeLastName":"Taylor",    "EmployeeDateOfBirth":new ISODate("1993-04-21 11:10:20"),    "EmployeeSkills":["C++","Cloud Computing"], "EmployeeDetails":[ {    "EmployeePerformanceArea":"C++", "Year":1998 }, { "EmployeePerformanceArea":"C++    Game Developer", "Year":2007 } ] } ); {    "acknowledged" : true,    "insertedId" : ObjectId("5c77b58f2386c62d05142a6b") }

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

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

The following is the output ?

{    "_id" : ObjectId("5c77b3812386c62d05142a6a"),    "EmployeeFirstName" : "Adam",    "EmployeeLastName" : "Smith",    "EmployeeDateOfBirth" : ISODate("1992-01-31T13:45:10Z"),    "EmployeeSkills" : [       "Spring and Hibernate Framework",       "Machine Learning"    ],    "EmployeeDetails" : [       {          "EmployeePerformanceArea" : "Java",          "Year" : 2001       },       {          "EmployeePerformanceArea" : "Python",          "Year" : 2005       }    ] } {    "_id" : ObjectId("5c77b58f2386c62d05142a6b"),    "EmployeeFirstName" : "Carol",    "EmployeeLastName" : "Taylor",    "EmployeeDateOfBirth" : ISODate("1993-04-21T11:10:20Z"),    "EmployeeSkills" : [       "C++",       "Cloud Computing"    ],    "EmployeeDetails" : [       {          "EmployeePerformanceArea" : "C++",          "Year" : 1998       },       {          "EmployeePerformanceArea" : "C++ Game Developer",          "Year" : 2007       }    ] }

Here is the query to search in an array of objects in MongoDB.

Case 1

When the given element is found.

The query is as follows ?

> db.searchArrayDemo.find({EmployeeDetails:{$elemMatch:{EmployeePerformanceArea : "C++", Year : 1998}}}).pretty();

The following is the output ?

{    "_id" : ObjectId("5c77b58f2386c62d05142a6b"),    "EmployeeFirstName" : "Carol",    "EmployeeLastName" : "Taylor",    "EmployeeDateOfBirth" : ISODate("1993-04-21T11:10:20Z"),    "EmployeeSkills" : [       "C++",       "Cloud Computing"    ],    "EmployeeDetails" : [       {          "EmployeePerformanceArea" : "C++",          "Year" : 1998       },       {          "EmployeePerformanceArea" : "C++ Game Developer",          "Year" : 2007       }    ] }

Case 2

When the given element is not found.

The query is as follows ?

> db.searchArrayDemo.find({EmployeeDetails:{$elemMatch:{EmployeePerformanceArea : "C", Year : 1996}}}).pretty();

Here you will not get anything when the given element is not found