tortoise.exceptions.OperationalError: the column must appear in the GROUP BY clause or be used in an aggregate function [Postgresql]

Model:

class Shop(Model):
    id = fields.BigIntField(pk=True, index=True)
    price = fields.BigIntField()

Code:

async def run():
    await Tortoise.init(db_url=f"postgres://...", modules={"models": ["models"]})
    await Tortoise.generate_schemas()

    for i in range(10):
        await Shop.get_or_create(price=i*1000)

    result = await Shop.all().annotate(price_avg=Avg("price")).first() # tortoise.exceptions.OperationalError: the column "shop.id" must appear in the GROUP BY clause or be used in an aggregate function [Postgresql]
    print(result)

>>> await Shop.all().annotate(price_avg=Avg("price")).sql()
SELECT "id","price",AVG("price") "avg" FROM "shop"

What am I doing wrong?

I understand that the error is due to the fact that the request for work should look like this: SELECT AVG("price") FROM Shop , but I didn't find how it can be normally implemented via orm.

Start with the provided Shop model and the Shop.all().annotate(price_avg=Avg("price")).sql() entry point, reproducing the generated SQL against PostgreSQL. Trace the aggregation query construction and compare it with PostgreSQL's GROUP BY requirement; done means the intended aggregate query has defined behavior and a focused regression test or usage guidance confirms it.