MongoDB provides a variety of comparison query operators. The $eq (equal to) operator is one of those operators. The $eq (equal to) operator is used to match the documents where the field's value is equal to the given value. In other words, the $eq operator is used to specify the condition of equality.
Syntax of the $eq operator:
Or
Examples:
In the following examples, we are working with:
>db.employee.find() { "_id" : 1, "name" : "John", "father_name" : "Thomas", "department" : "Contain Writting", "experience" : 2, "language" : { "C#", "python", "java" }, "mobile_no" : 9856321478, "gender" : "Male", "salary" : 22000, "age" : 26 } { "_id" : 2, "name" : "William", "father_name" : "Rebort", "department" : "Softwre Tester", "experience" : 1, "language" : { "C#", "python" }, "mobile_no" : 7896541478, "gender" : "Male", "salary" : 20000, "age" : 21 } { "_id" : 3, "name" : "Ava", "father_name" : "William", "department" : "Marketing manager", "experience" : 5, "language" : { "C#", "C++", "java" }, "mobile_no" : 8789654178, "gender" : "Female", "salary" : 36500, "age" : 25 } { "_id" : 4, "name" : "Olivia", "father_name" : "Noah", "department" : null, "experience" : 4, "language" : { "C++", "java" }, "mobile_no" : 9045641478, "gender" : "Female", "salary" : 30000, "age" : 27 } { "_id" : 5, "name" : "Elijah", "father_name" : "John", "department" : "HR", "experience" : 0, "language" : { "C++", "HTML", "java" }, "mobile_no" : 6589741230, "gender" : "Male", "salary" : 15000, "age" : 20 } { "_id" : 6, "name" : "John", "father_name" : "Liam", "department" : "Softwre Tester", "experience" : 10, "language" : { "C#", "CSS", "HTML" }, "mobile_no" : 9014536987, "gender" : "Male", "salary" : 55000, "age" : 30 }
Example 1: Using $eq operator
In this example, we are looking for documents whose gender field is equal to male.
Or
Output:
{ "_id" : 1, "name" : "John", "father_name" : "Thomas", "department" : "Contain Writting", "experience" : 2, "language" : { "C#", "python", "java" }, "mobile_no" : 9856321478, "gender" : "Male", "salary" : 22000, "age" : 26 } { "_id" : 2, "name" : "William", "father_name" : "Rebort", "department" : "Softwre Tester", "experience" : 1, "language" : { "C#", "python"}, "mobile_no" : 7896541478, "gender" : "Male", "salary" : 20000, "age" : 21 } { "_id" : 5, "name" : "Elijah", "father_name" : "John", "department" : "HR", "experience" : 0, "language" : { "C++", "HTML", "java" }, "mobile_no" : 6589741230, "gender" : "Male", "salary" : 15000, "age" : 20 } { "_id" : 6, "name" : "John", "father_name" : "Liam", "department" : "Softwre Tester", "experience" : 10, "language" : { "C#", "CSS", "HTML" }, "mobile_no" : 9014536987, "gender" : "Male", "salary" : 55000, "age" : 30 }
Example 2: Another example
In this example, we're looking for documents that employees work on the "C++" language.
Or
Output:
{ "_id" : 3, "name" : "Ava", "father_name" : "William", "department" : "Marketing manager", "experience" : 5, "language" : { "C#", "C++", "java" }, "mobile_no" : 8789654178, "gender" : "Female", "salary" : 36500, "age" : 25 } { "_id" : 4, "name" : "Olivia", "father_name" : "Noah", "department" : null, "experience" : 4, "language" : { "C++", "java" }, "mobile_no" : 9045641478, "gender" : "Female", "salary" : 30000, "age" : 27 } { "_id" : 5, "name" : "Elijah", "father_name" : "John", "department" : "HR", "experience" : 0, "language" : { "C++", "HTML", "java" }, "mobile_no" : 6589741230, "gender" : "Male", "salary" : 15000, "age" : 20 }