Fixed #29850 -- Added exclusion support to RowRange and ValueRange.

django/db/backends/base/features.py

@@ -264,6 +264,7 @@ class BaseDatabaseFeatures:
     supports_over_clause = False
     supports_frame_range_fixed_distance = False
     only_supports_unbounded_with_preceding_and_following = False
+    supports_frame_exclusion = False
 
     # Does the backend support CAST with precision?
     supports_cast_with_precision = True

django/db/backends/oracle/features.py

@@ -162,3 +162,7 @@ def supports_collation_on_charfield(self):
     @cached_property
     def supports_primitives_in_json_field(self):
         return self.connection.oracle_version >= (21,)
+
+    @cached_property
+    def supports_frame_exclusion(self):
+        return self.connection.oracle_version >= (21,)

django/db/backends/postgresql/features.py

@@ -62,6 +62,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     requires_casted_case_in_updates = True
     supports_over_clause = True
     only_supports_unbounded_with_preceding_and_following = True
+    supports_frame_exclusion = True
     supports_aggregate_filter_clause = True
     supported_explain_formats = {"JSON", "TEXT", "XML", "YAML"}
     supports_deferrable_unique_constraints = True

django/db/backends/sqlite3/features.py

@@ -32,6 +32,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     can_defer_constraint_checks = True
     supports_over_clause = True
     supports_frame_range_fixed_distance = Database.sqlite_version_info >= (3, 28, 0)
+    supports_frame_exclusion = Database.sqlite_version_info >= (3, 28, 0)
     supports_aggregate_filter_clause = Database.sqlite_version_info >= (3, 30, 1)
     supports_order_by_nulls_modifier = Database.sqlite_version_info >= (3, 30, 0)
     # NULLS LAST/FIRST emulation on < 3.30 requires subquery wrapping.

django/db/models/__init__.py

@@ -19,6 +19,7 @@
 from django.db.models.enums import __all__ as enums_all
 from django.db.models.expressions import (
     Case,
+    Exclusion,
     Exists,
     Expression,
     ExpressionList,
@@ -76,6 +77,7 @@
     "ProtectedError",
     "RestrictedError",
     "Case",
+    "Exclusion",
     "Exists",
     "Expression",
     "ExpressionList",

django/db/models/expressions.py

@@ -4,6 +4,7 @@
 import inspect
 from collections import defaultdict
 from decimal import Decimal
+from enum import Enum
 from types import NoneType
 from uuid import UUID
 
@@ -1848,6 +1849,13 @@ def get_group_by_cols(self):
         return group_by_cols
 
 
+class Exclusion(Enum):
+    CURRENT_ROW = "CURRENT ROW"
+    GROUP = "GROUP"
+    TIES = "TIES"
+    NO_OTHERS = "NO OTHERS"
+
+
 class WindowFrame(Expression):
     """
     Model the frame clause in window expressions. There are two types of frame
@@ -1859,23 +1867,37 @@ class WindowFrame(Expression):
 
     template = "%(frame_type)s BETWEEN %(start)s AND %(end)s"
 
-    def __init__(self, start=None, end=None):
+    def __init__(self, start=None, end=None, exclusion=None):
         self.start = Value(start)
         self.end = Value(end)
+        self.exclusion = exclusion
 
     def set_source_expressions(self, exprs):
         self.start, self.end = exprs
 
     def get_source_expressions(self):
         return [self.start, self.end]
 
+    def get_exclusion(self):
+        if not connection.features.supports_frame_exclusion:
+            raise NotSupportedError(
+                "This backend does not support window frame exclusions."
+            )
+        if self.exclusion in Exclusion.__members__.values():
+            return f"EXCLUDE {self.exclusion.value}"
+        raise ValueError("exclusion must be a valid Exclusion value.")
+
     def as_sql(self, compiler, connection):
         connection.ops.check_expression_support(self)
         start, end = self.window_frame_start_end(
             connection, self.start.value, self.end.value
         )
+        window_frame_template_parts = [self.template]
+        if self.exclusion is not None:
+            exclusion_as_sql = self.get_exclusion()
+            window_frame_template_parts.append(exclusion_as_sql)
         return (
-            self.template
+            " ".join(window_frame_template_parts)
             % {
                 "frame_type": self.frame_type,
                 "start": start,
@@ -1908,7 +1930,11 @@ def __str__(self):
             end = "%d %s" % (abs(self.end.value), connection.ops.PRECEDING)
         else:
             end = connection.ops.UNBOUNDED_FOLLOWING
-        return self.template % {
+
+        window_frame_template_parts = [self.template]
+        if self.exclusion in Exclusion.__members__.values():
+            window_frame_template_parts.append(f"EXCLUDE {self.exclusion.value}")
+        return " ".join(window_frame_template_parts) % {
             "frame_type": self.frame_type,
             "start": start,
             "end": end,

docs/ref/models/expressions.txt

@@ -889,7 +889,7 @@ Frames
 For a window frame, you can choose either a range-based sequence of rows or an
 ordinary sequence of rows.
 
-.. class:: ValueRange(start=None, end=None)
+.. class:: ValueRange(start=None, end=None, exclusion=None)
 
     .. attribute:: frame_type
 
@@ -899,7 +899,7 @@ ordinary sequence of rows.
     the standard start and end points, such as ``CURRENT ROW`` and ``UNBOUNDED
     FOLLOWING``.
 
-.. class:: RowRange(start=None, end=None)
+.. class:: RowRange(start=None, end=None, exclusion=None)
 
     .. attribute:: frame_type
 
@@ -911,6 +911,27 @@ Both classes return SQL with the template:
 
     %(frame_type)s BETWEEN %(start)s AND %(end)s
 
+
+.. class:: Exclusion
+
+    .. versionadded:: 5.1
+
+    .. attribute:: CURRENT_ROW
+
+    .. attribute:: GROUP
+
+    .. attribute:: TIES
+
+    .. attribute:: NO_OTHERS
+
+If ``exclusion`` is an attribute of
+:class:`~django.db.models.expressions.Exclusion`, this returns for supported
+databases:
+
+.. code-block:: sql
+
+    %(frame_type)s BETWEEN %(start)s AND %(end)s EXCLUDE (exclusion)s
+
 Frames narrow the rows that are used for computing the result. They shift from
 some start point to some specified end point. Frames can be used with and
 without partitions, but it's often a good idea to specify an ordering of the
@@ -976,7 +997,8 @@ released between twelve months before and twelve months after the each movie:
 .. versionchanged:: 5.1
 
     Support for positive integer ``start`` and negative integer ``end`` was
-    added for ``RowRange``.
+    added for ``RowRange``. ``exclusion`` was added to ``RowRange`` and
+    ``ValueRange``.
 
 .. currentmodule:: django.db.models
 

docs/releases/5.1.txt

@@ -174,6 +174,11 @@ Models
 * :class:`~django.db.models.expressions.RowRange` now accept positive integers
   for the ``start`` argument and negative integers for the ``end`` argument.
 
+* The new ``exclusion`` argument of
+  :class:`~django.db.models.expressions.RowRange` and
+  :class:`~django.db.models.expressions.ValueRange` adds an exclusion clause to
+  the generated SQL when set to a  for supported databases.
+
 Requests and Responses
 ~~~~~~~~~~~~~~~~~~~~~~