Mysql Current Winning streak - mysql

Question

I have been trying to get the current winning streak based on a results table. I am having lots of trouble with this though. I have managed to get what the teams highest win streak for each team over the full period is. But what I cannot manage to do is get the current win streak if they have one based on the last result per team.
For example the below table where the result is 'H' indicated as win.
TeamID Result Date
25 A 02/12/17
25 H 16/12/17
25 D 22/12/17
25 D 03/01/18
25 H 20/01/18
28 D 09/12/17
28 D 23/12/17
28 H 01/01/18
28 H 20/01/18
58 H 02/12/17
58 A 16/12/17
58 H 23/12/17
58 H 01/01/18
58 D 20/01/18
61 D 03/12/17
61 A 17/12/17
61 D 26/12/17
61 H 30/12/17
61 H 14/01/18
So TeamID 25 has a current win streak of 1. TeamID 28 a win streak of 2 and Team 58 a win streak of 0 as there last result was 'D' (Draw)
I have used the below code which I can get working but not with the additional grouping the results come back all as 1 which is clearly wrong.
http://www.sqlteam.com/article/detecting-runs-or-streaks-in-your-data
I have looked at other bits of code on here but none of them appear to be based on the last result or they are SQL Server based but I need the code to work in MySQL. Thanks for any help on this.

Answer 1

How to ask a question;
DROP TABLE IF EXISTS my_table;
CREATE TABLE my_table
(TeamID INT NOT NULL
,Result CHAR(1) NOT NULL
,Date DATE NOT NULL
,PRIMARY KEY(teamid,date)
);
INSERT INTO my_table VALUES
(25,'A','2017-12-02'),
(25,'H','2017-12-16'),
(25,'D','2017-12-22'),
(25,'D','2018-01-03'),
(25,'H','2018-01-20'),
(28,'D','2017-12-09'),
(28,'D','2017-12-23'),
(28,'H','2018-01-01'),
(28,'H','2018-01-20'),
(58,'H','2017-12-02'),
(58,'A','2017-12-16'),
(58,'H','2017-12-23'),
(58,'H','2018-01-01'),
(58,'D','2018-01-20'),
(61,'D','2017-12-03'),
(61,'A','2017-12-17'),
(61,'D','2017-12-26'),
(61,'H','2017-12-30'),
(61,'H','2018-01-14');
How to answer one:
SELECT a.*
FROM
( SELECT x.*
, CASE WHEN #prev=teamid THEN CASE WHEN result = 'H' THEN #i:=#i+1 ELSE #i:=0 END ELSE #i:=0 END i
, #prev:=teamid prev
FROM my_table x
, (SELECT #prev:=null,#i:=0) vars
ORDER
BY teamid
, date
) a
JOIN
( SELECT teamid
, MAX(date) date
FROM my_table
GROUP
BY teamid
) b
ON b.teamid = a.teamid
AND b.date = a.date;
+--------+--------+------------+------+------+
| TeamID | Result | Date | i | prev |
+--------+--------+------------+------+------+
| 25 | H | 2018-01-20 | 1 | 25 |
| 28 | H | 2018-01-20 | 2 | 28 |
| 58 | D | 2018-01-20 | 0 | 58 |
| 61 | H | 2018-01-14 | 2 | 61 |
+--------+--------+------------+------+------+