groups = self.env['your_model'].read_group([], ['date', 'amount'], ['date'])
for group in groups:
print('>>>>>>', group['date_count'], group['amount'])
odoo v12 support group by 'month', 'week', 'day' like
groups = self.env['your_model'].read_group([], ['date', 'amount'], ['date:day'])
for group in groups:
print('>>>>>>', group['date:day'],group['date_count'], group['amount'])