Currently exploring the MongoDB aggregation framework, let's consider a collection structured like this:
[
{
_id: ObjectId(123)
name: john,
sessionDuration: 29
},
{
_id: ObjectId(456)
name: moore,
sessionDuration: 45
},
{
_id: ObjectId(789)
name: cary,
sessionDuration: 25
},
]
The goal is to devise a query and pipeline that produces output in this format:
{
durationsArr: [29, 49, 25, '$sessionDuration_Field_From_Document' ];
}
This setup enables the calculation of the average duration across all documents. By aggregating the data into an array initiallly, the $avg operation can be carried out effectively in the final stage.
Seeking advice on how to retrieve the array for the sessionDurationField, or alternative optimal strategies for determining the average sessionDuration from the collection. Appreciate a detailed explanation as I am relatively new to MongoDB aggregation.