Group elements by date and get elements id list from group.

date_group.sql

SELECT DATE_FORMAT(d, "%Y%m") as month_year, GROUP_CONCAT(id SEPARATOR ',') as ids FROM events_event GROUP BY month_year LIMIT 100

django_orm.py

from django.db.models.aggregates import Aggregate
from django.db.models.sql.aggregates import Aggregate as SQLAggregate

class SQLConcat(SQLAggregate):
    sql_function = "GROUP_CONCAT"
    def __init__(self, col, separator=',', **extra):
        self.sql_template = "%%(function)s(%%(field)s SEPARATOR '%s')" % separator
        super(SQLConcat, self).__init__(col, source=models.DecimalField(), **extra)

class Concat(Aggregate):
    name = "Concat"

    def add_to_query(self, query, alias, col, source, is_summary):
        aggregate = SQLConcat(col, is_summary=is_summary, **self.extra)
        query.aggregates[alias] = aggregate
        
out = Event.objects.filter(d__lt=datetime.now()).extra(select={
	'month_year': 'DATE_FORMAT(d, "%%m.%%Y")',
	}).values('month_year').annotate(count=Concat('id'))