id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
37316	Functions need a way to mark themselves as volatile	Jacob Walls		"In the ORM, expressions are hashed based on their type and arguments. Because random functions like `UUID7()` aren't marked as volatile, repeated expressions can hash to the same thing, leading to inappropriate deduplication later when compiling `ORDER BY` and `GROUP BY`:

For example, these group by expressions get deduplicated:
{{{#!py
from django.contrib.auth.models import User
from django.db import models
from django.db.models.functions import Floor, Random

def roll(faces):
    return Floor(Random() * faces) + 1

def run():
    User.objects.bulk_create([User(username=str(i)) for i in range(1, 13)])
    
    qs = User.objects.values(
        first_roll=roll(6),
        tie_break_roll=roll(6),
    ).annotate(total=models.Count(""pk""))
    print(qs)
}}}

{{{#!sql
SELECT (FLOOR((RANDOM() * 6)) + 1) AS ""first_roll"",
       (FLOOR((RANDOM() * 6)) + 1) AS ""tie_break_roll"",
       COUNT(""auth_user"".""id"") AS ""total""
FROM ""auth_user""
GROUP BY 2
LIMIT 21
}}}

I would have expected `GROUP BY 1, 2`.

In addition to `GROUP BY`, some other areas to check are deduplication in `ORDER BY`, `get_extra_select()` for `distinct()`, and `get_qualify_sql()` for `Window()` functions.

Noticed while reviewing #37222."	New feature	new	Database layer (models, ORM)	dev	Normal				Unreviewed	0	0	0	0	0	0