django-lastdayofmonth

django‑lastdayofmonth

Cross‑database LastDayOfMonth ORM function for Django.

Calculate the last calendar day of any month directly in the database, with the same API on SQLite, PostgreSQL, MySQL/MariaDB and Oracle.

Installation

pip install django-lastdayofmonth

That’s it — no settings tweaks required.
Simply import the helper wherever you need it (see Quick usage for an example).

Compatibility matrix

Django version	Python version	Supported back‑ends
3.2 LTS → 5.2 LTS	3.8 → 3.12	SQLite, PostgreSQL ≥ 12, MySQL ≥ 5.7 / MariaDB ≥ 10.4, Oracle ≥ 19c

The library is fully tested in CI across all the combinations above.

Quick usage

from django.db.models import DateField
from django_lastdayofmonth import LastDayOfMonth

# annotate each invoice with the month‑end date of its `issued_date`
Invoice.objects.annotate(
    month_end=LastDayOfMonth("issued_date")
)

LastDayOfMonth works in annotate(), filter(), aggregate(), etc.

Why?

Calculating month‑end boundaries in Python causes heavy data transfer and breaks query optimisations. Leveraging the database engine keeps logic in SQL and stays performant.

Running tests locally

pip install tox pytest pytest-django dj-database-url mysqlclient oracledb psycopg2-binary  # install testing and DB driver dependencies
pytest -q --reuse-db                 # run tests locally

Use tox to run the full matrix (tox -p auto). See .github/workflows/ci.yml for Docker examples of each database.

License

Released under the MIT license. See the LICENSE file for details.