MySQL 8.0

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CREATE TABLE tablename (
  `id` INTEGER,
  `price` FLOAT,
  `date` DATETIME
);

INSERT INTO tablename
  (`id`, `price`, `date`)
VALUES
  ('1', '4.45', '2016-05-16'),
  ('1', '8.46', '2016-05-16'),
  ('2', '11.9', '2016-05-16'),
  ('3', '6.76', '2016-05-16'),
  ('3', '13.55', '2016-05-16'),
  ('4', '4.91', '2016-05-20'),
  ('1', '16.77', '2016-05-20'),
  ('3', '16.18', '2016-05-20'),
  ('2', '6.07', '2016-05-20'),
  ('4', '6.25', '2016-05-20');
SELECT COALESCE(date, 'Overall') date, 
       COALESCE(id, 'Total') id, 
       ROUND(AVG(price), 2) avg_price
FROM tablename
GROUP BY date, id
WITH ROLLUP;


date
id
avg_price


2016-05-16 00:00:00
1
6.45

2016-05-16 00:00:00
2
11.9

2016-05-16 00:00:00
3
10.16

2016-05-16 00:00:00
Total
9.02

2016-05-20 00:00:00
1
16.77

2016-05-20 00:00:00
2
6.07

2016-05-20 00:00:00
3
16.18

2016-05-20 00:00:00
4
5.58

2016-05-20 00:00:00
Total
10.04

Overall
Total
9.53


SELECT CASE WHEN GROUPING(date) THEN 'Overall' ELSE date END date, 
       CASE WHEN GROUPING(id) THEN 'Total' ELSE id END id, 
       ROUND(AVG(price), 2) avg_price
FROM tablename
GROUP BY date, id
WITH ROLLUP;


date
id
avg_price


2016-05-16 00:00:00
1
6.45

2016-05-16 00:00:00
2
11.9

2016-05-16 00:00:00
3
10.16

2016-05-16 00:00:00
Total
9.02

2016-05-20 00:00:00
1
16.77

2016-05-20 00:00:00
2
6.07

2016-05-20 00:00:00
3
16.18

2016-05-20 00:00:00
4
5.58

2016-05-20 00:00:00
Total
10.04

Overall
Total
9.53

date	id	avg_price
2016-05-16 00:00:00	1	6.45
2016-05-16 00:00:00	2	11.9
2016-05-16 00:00:00	3	10.16
2016-05-16 00:00:00	Total	9.02
2016-05-20 00:00:00	1	16.77
2016-05-20 00:00:00	2	6.07
2016-05-20 00:00:00	3	16.18
2016-05-20 00:00:00	4	5.58
2016-05-20 00:00:00	Total	10.04
Overall	Total	9.53