Computer scienceFundamentalsSQL and DatabasesDBMSMongoDBOperations and operators

Aggregate operations

Aggregation pipeline

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Suppose we have a collection called employees that contains documents with the following fields:

employee_id, first_name, last_name, department and salary.

We want to find the average salary for employees in each department and sort the result in a descending order.

Select one option from the list

db.employees.aggregate([ { $group: { _id: "$employee_id", averageSalary: { $avg: "$salary" } } }, { $sort: { averageSalary: -1 } } ])

db.employees.aggregate([ { $group: { _id: "$department", averageSalary: { $avg: "$salary" } } }, { $sort: { averageSalary: -1 } } ])

db.employees([ { $group: { _id: "$department", averageSalary: { $avg: "$salary" } } }, { $sort: { averageSalary: -1 } } ])

db.employees.aggregate([ { $group: { _id: "$department", averageSalary: { $count: "$salary" } } }, { $sort: { averageSalary: -1 } } ])

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