MySQL 5.7

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select version();


version()


5.7.34


CREATE TABLE item
(
  item_symbol CHAR(1), 
  price       DECIMAL(10,2), 
  source_date DATE
);
INSERT INTO item
(item_symbol, price, source_date)
VALUES
('A', 20.1, '2021-06-10'),
('A', 18.2, '2021-06-11'),
('A', 10.9, '2021-06-13'),
('A', 21.0, '2021-06-15'),
('B', 88.2, '2021-06-10'),
('B', 60.9, '2021-06-11'),
('B', 78.16, '2021-06-13'),
('B', 79.0, '2021-06-15');
SELECT * FROM item;


item_symbol
price
source_date


A
20.10
2021-06-10

A
18.20
2021-06-11

A
10.90
2021-06-13

A
21.00
2021-06-15

B
88.20
2021-06-10

B
60.90
2021-06-11

B
78.16
2021-06-13

B
79.00
2021-06-15


SELECT
  item_symbol, price, source_date,
  IF 
  (
    @prev <> item_symbol,
    @row_num := 1,
    @row_num := @row_num + 1
  ) AS my_rank,
  @prev := item_symbol
FROM item
JOIN 
  (
    SELECT @row_num := NULL, @prev := 0
  ) AS r
ORDER BY item_symbol, source_date DESC, price DESC;


item_symbol
price
source_date
my_rank
@prev := item_symbol


A
21.00
2021-06-15
1
A

A
10.90
2021-06-13
2
A

A
18.20
2021-06-11
3
A

A
20.10
2021-06-10
4
A

B
79.00
2021-06-15
1
B

B
78.16
2021-06-13
2
B

B
60.90
2021-06-11
3
B

B
88.20
2021-06-10
4
B


SELECT item_symbol, price, source_date, my_rank  -- this last one is not 
FROM                                             -- required - for clarity...
(
  SELECT
    item_symbol, price, source_date,
    IF 
    (
      @prev <> item_symbol,
      @row_num := 1,
      @row_num := @row_num + 1
    ) AS my_rank,
    @prev := item_symbol
    FROM item
    JOIN (SELECT @row_num := NULL, @prev := 0) AS r
    ORDER BY item_symbol, source_date DESC, price DESC  -- in case of ties!
) AS t
WHERE t.my_rank <= 2
ORDER BY item_symbol, source_date DESC; -- change this as required


item_symbol
price
source_date
my_rank


A
21.00
2021-06-15
1

A
10.90
2021-06-13
2

B
79.00
2021-06-15
1

B
78.16
2021-06-13
2

item_symbol	price	source_date
A	20.10	2021-06-10
A	18.20	2021-06-11
A	10.90	2021-06-13
A	21.00	2021-06-15
B	88.20	2021-06-10
B	60.90	2021-06-11
B	78.16	2021-06-13
B	79.00	2021-06-15