Django SQL Window Functions (functions/window.py)

Provides Django ORM expressions for SQL window functions like Rank and Lag. Reuse when building complex database queries.

# Source: https://github.com/django/django | License: BSD-3-Clause | Copyright Django Software Foundation and individual contributors
# Provided via justclaw.it.com; keep this notice with the code.
from django.db.models.expressions import Func
from django.db.models.fields import FloatField, IntegerField

__all__ = [
    "CumeDist",
    "DenseRank",
    "FirstValue",
    "Lag",
    "LastValue",
    "Lead",
    "NthValue",
    "Ntile",
    "PercentRank",
    "Rank",
    "RowNumber",
]


class CumeDist(Func):
    function = "CUME_DIST"
    output_field = FloatField()
    window_compatible = True


class DenseRank(Func):
    function = "DENSE_RANK"
    output_field = IntegerField()
    window_compatible = True


class FirstValue(Func):
    arity = 1
    function = "FIRST_VALUE"
    window_comp

... (truncated -- full source via MCP)