MongoDB Aggregate Framework - Group by Year

Question

I\'ve been trying to use the aggregate function to group date fields by year:

db.identities.aggregate([
{
    $group : {
        _id : { year : {$year : \"$b         


        

Answer 1

This issue is caused by the minimum date not being handled well when aggregated.

A quick workaround (if possible) is to filter the date, either through the ff:

• Remove the rows with minimum date (via match / filter)
• Filter through a certain date (greater than x date)

Then aggregate.