how to track score gains in mysql - mysql

Question

I would like to display a players current score as well as how many points they have gained within a selected time frame.
I have 2 tables
skills table
+----+---------+---------------------+
| id | name | created_at |
+----+---------+---------------------+
| 1 | skill 1 | 2020-06-05 00:00:00 |
| 2 | skill 2 | 2020-06-05 00:00:00 |
| 3 | skill 3 | 2020-06-05 00:00:00 |
+----+---------+---------------------+
scores table
+----+-----------+----------+-------+---------------------+
| id | player_id | skill_id | score | created_at |
+----+-----------+----------+-------+---------------------+
| 1 | 1 | 1 | 5 | 2020-06-06 00:00:00 |
| 2 | 1 | 1 | 10 | 2020-07-06 00:00:00 |
| 3 | 1 | 2 | 1 | 2020-07-06 00:00:00 |
| 4 | 2 | 1 | 11 | 2020-07-06 00:00:00 |
| 5 | 1 | 1 | 13 | 2020-07-07 00:00:00 |
| 6 | 1 | 2 | 10 | 2020-07-07 00:00:00 |
| 7 | 2 | 1 | 12 | 2020-07-07 00:00:00 |
| 8 | 1 | 1 | 20 | 2020-07-08 00:00:00 |
| 9 | 1 | 2 | 15 | 2020-07-08 00:00:00 |
| 10 | 2 | 1 | 17 | 2020-07-08 00:00:00 |
+----+-----------+----------+-------+---------------------+
my expected results are:-
24 hour query
+-----------+---------+-------+------+
| player_id | name | score | gain |
+-----------+---------+-------+------+
| 1 | skill 1 | 20 | 7 |
| 1 | skill 2 | 15 | 5 |
+-----------+---------+-------+------+
7 day query
+-----------+---------+-------+------+
| player_id | name | score | gain |
+-----------+---------+-------+------+
| 1 | skill 1 | 20 | 10 |
| 1 | skill 2 | 15 | 14 |
+-----------+---------+-------+------+
31 day query
+-----------+---------+-------+------+
| player_id | name | score | gain |
+-----------+---------+-------+------+
| 1 | skill 1 | 20 | 15 |
| 1 | skill 2 | 15 | 14 |
+-----------+---------+-------+------+
so far I have the following, but all this does is return the last 2 records for each skill, I am struggling to calculate the gains and the different time frames
SELECT player_id, skill_id, name, score
FROM (SELECT player_id, skill_id, name, score,
#skill_count := IF(#current_skill = skill_id, #skill_count + 1, 1) AS skill_count,
#current_skill := skill_id
FROM skill_scores
INNER JOIN skills
ON skill_id = skills.id
WHERE player_id = 1
ORDER BY skill_id, score DESC
) counted
WHERE skill_count <= 2
I would like some help figuring out the query I need to build to get the desired results, or is it best to do this with php instead of in the db?
EDIT:-
MYSQL 8.0.20 dummy data id's are primary_key auto increment but I didnt ad that for simplicity:-
CREATE TABLE skills
(
id bigint,
name VARCHAR(80)
);
CREATE TABLE skill_scores
(
id bigint,
player_id bigint,
skill_id bigint,
score bigint,
created_at timestamp
);
INSERT INTO skills VALUES (1, 'skill 1');
INSERT INTO skills VALUES (2, 'skill 2');
INSERT INTO skills VALUES (3, 'skill 3');
INSERT INTO skill_scores VALUES (1, 1, 1 , 5, '2020-06-06 00:00:00');
INSERT INTO skill_scores VALUES (2, 1, 1 , 10, '2020-07-06 00:00:00');
INSERT INTO skill_scores VALUES (3, 1, 2 , 1, '2020-07-06 00:00:00');
INSERT INTO skill_scores VALUES (4, 2, 1 , 11, '2020-07-06 00:00:00');
INSERT INTO skill_scores VALUES (5, 1, 1 , 13, '2020-07-07 00:00:00');
INSERT INTO skill_scores VALUES (6, 1, 2 , 10, '2020-07-07 00:00:00');
INSERT INTO skill_scores VALUES (7, 2, 1 , 12, '2020-07-07 00:00:00');
INSERT INTO skill_scores VALUES (8, 1, 1 , 20, '2020-07-08 00:00:00');
INSERT INTO skill_scores VALUES (9, 1, 2 , 15, '2020-07-08 00:00:00');
INSERT INTO skill_scores VALUES (10, 2, 1 , 17, '2020-07-08 00:00:00');

Answer 1

WITH cte AS (
SELECT id, player_id, skill_id,
FIRST_VALUE(score) OVER (PARTITION BY player_id, skill_id ORDER BY created_at DESC) score,
FIRST_VALUE(score) OVER (PARTITION BY player_id, skill_id ORDER BY created_at DESC) - FIRST_VALUE(score) OVER (PARTITION BY player_id, skill_id ORDER BY created_at ASC) gain,
ROW_NUMBER() OVER (PARTITION BY player_id, skill_id ORDER BY created_at DESC) rn
FROM skill_scores
WHERE created_at BETWEEN #current_date - INTERVAL #interval DAY AND #current_date
)
SELECT cte.player_id, skills.name, cte.score, cte.gain
FROM cte
JOIN skills ON skills.id = cte.skill_id
WHERE rn = 1
ORDER BY player_id, name;
fiddle
Ps. I don't understand where gain=15 is taken for 31-day period - the difference between '2020-07-08 00:00:00' and '2020-06-06 00:00:00' is 32 days.

Answer 2

Well i think you need a (temporary) table for this. I will call it "player_skill_gains". Its basically the players skills ordered by created_at and with an auto_incremented id:
CREATE TABLE player_skill_gains
(`id` int PRIMARY KEY AUTO_INCREMENT NOT NULL
, `player_id` int
, skill_id int
, score int
, created_at date)
;
INSERT INTO player_skill_gains(player_id, skill_id, score, created_at)
SELECT player_skills.player_id AS player_id
, player_skills.skill_id
, SUM(player_skills.score) AS score
, player_skills.created_at
FROM player_skills
GROUP BY player_skills.id, player_skills.skill_id, player_skills.created_at
ORDER BY player_skills.player_id, player_skills.skill_id, player_skills.created_at ASC;
Using this table we can relatively easily select the last skill for each row (id-1). Using this we can calculate the gains:
SELECT player_skill_gains.player_id, skills.name, player_skill_gains.score
, player_skill_gains.score - IFNULL(bef.score,0) AS gain
, player_skill_gains.created_at
FROM player_skill_gains
INNER JOIN skills ON player_skill_gains.skill_id = skills.id
LEFT JOIN player_skill_gains AS bef ON (player_skill_gains.id - 1) = bef.id
AND player_skill_gains.player_id = bef.player_id
AND player_skill_gains.skill_id = bef.skill_id
For the different queries you want to have (24 hours, 7 days, etc.) you just have to specify the needed where-part for the query.
You can see all this in action here: http://sqlfiddle.com/#!9/1571a8/11/0