Does the ORM read_group on Odoo 11 has the same features of Odoo 12? - group-by

Question

I am working on an Odoo 11 project and unfortunately, we can't migrate to Odoo 12.
Reading the book Odoo 12 Development Cookbook - Third Edition I found a way to create my aggregate method WITHOUT coding SQL with GROUP BY, just using the read_group method available on Odoo API.
Here is what I do to get it using SQL:
SELECT SUM(ai.amount_total) as sum_total,
AVG(ai.amount_total) as avg_total
FROM account_invoice as ai
WHERE ai.partner_id = :partner_id AND ai.type = 'out_invoice'
And here is how I am trying to get it working on my model class:
class MyModel(models.Model):
# fields definition
#api.multi
def get_aggregated_invoices(self):
self.ensure_one()
invoices_partner_domain = [
('partner_id', '=', self.partner_id.id),
('type', '=', 'out_invoice')
]
grouped_result = self.env['account.invoice'].read_group(
invoices_partner_domain,
[
'partner_id',
'sum_total:sum(amount_total)',
'avg_total:avg(amount_total)'
],
['partner_id']
)
if len(grouped_result) > 0:
print(str(grouped_result)) # << DEBUG breakpoint here
return {
'sum_total': grouped_result[0]['sum_total'],
'sum_total': grouped_result[0]['avg_total'],
}
else:
return None
Debugging the code I got this result:
Am I missing anything or Odoo 11 does not have the same features as Odoo 12?
If not, is there any way to do it through Odoo API or should I need to stick with my GROUP BY SQL statement instead?

Answer 1

The v12 version introduces the use of aggregation functions in fields parameter.
:param list fields: list of fields present in the list view specified on the object.
Each element is either field (field name, using the default aggregation),
or field:agg (aggregate field with aggregation function agg),
or name:agg(field) (aggregate field with agg and return it as name).
The possible aggregation functions are the ones provided by PostgreSQL
(https://www.postgresql.org/docs/current/static/functions-aggregate.html)
and count_distinct, with the expected meaning.
The difference is in the process of the aggregated field in the _read_group_raw function, Odoo will try to use the aggregation function if defined and valid, if not it will use the field group_operator as an aggregation function.
Odoo 11 will not check if we defined an aggregation function and use the group_operator. In your example, the aggregated_fields will be an empty list.
The default group_operator for amount_total field is sum. If you use the SQL debug level, you will see that Odoo executes the following query:
SELECT min("account_invoice".id) AS id, count("account_invoice".id) AS "partner_id_count" , sum("account_invoice"."amount_total") AS "amount_total" ,"account_invoice"."partner_id" as "partner_id"
FROM "account_invoice" LEFT JOIN "res_partner" as "account_invoice__partner_id" ON ("account_invoice"."partner_id" = "account_invoice__partner_id"."id")
WHERE (("account_invoice"."partner_id" = %s) AND ("account_invoice"."type" = %s))
GROUP BY "account_invoice"."partner_id","account_invoice__partner_id"."display_name"
ORDER BY "account_invoice__partner_id"."display_name"
When calling the read_group function as following (use sum as an aggregation function):
grouped_result = self.env['account.invoice'].read_group(
invoices_partner_domain,
[
'partner_id',
'amount_total',
],
['partner_id']
)