mongodbHow to aggregate in MongoDB?
MongoDB provides several ways to aggregate data from collections. The most common way is to use the aggregate()
method. This method takes an array of pipeline stages as its argument and returns the aggregated result.
Example
db.collection.aggregate([
{
$group: {
_id: "$department",
totalSalary: { $sum: "$salary" }
}
}
])
Output example
{ "_id" : "IT", "totalSalary" : 15000 }
{ "_id" : "HR", "totalSalary" : 12000 }
Code explanation
aggregate()
: The method used to aggregate data from collections.$group
: The operator used to group documents by a specified field and perform an aggregation on them._id
: The field used to specify the field to group by.$sum
: The operator used to sum the values of a specified field.
Helpful links
More of Mongodb
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- How to empty an array in MongoDB?
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- How to work with time series data in MongoDB?
- How to rename a field in MongoDB?
- How to convert MongoDB ObjectId to string?
- How to perform a health check for MongoDB?
- How to group in MongoDB?
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