Select maximum value of each member from table [duplicate] - mysql

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This question already has answers here:
Fetch the rows which have the Max value for a column for each distinct value of another column
(35 answers)
Closed 8 years ago.
I want to select the best result of each member from the mysql table, for a given discipline.
(if there are entries with the same value, the entries with the lowest event start date should be taken)
DDLs:
CREATE TABLE `results` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`discipline` int(11) NOT NULL,
`member` int(11) DEFAULT '0',
`event` int(11) DEFAULT '0',
`value` int(11) DEFAULT '0',
PRIMARY KEY (`id`),
UNIQUE KEY `member_2` (`member`,`discipline`,`event`)
);
INSERT INTO results VALUES
(1,1,2,4,10),
(2,1,1,4, 8),
(3,1,2,5, 9),
(4,2,3,5, 9),
(5,1,2,6,11),
(6,1,2,7,11),
(7,1,2,1,11),
(8,1,2,3, 7);
CREATE TABLE `events` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(50) DEFAULT NULL,
`startDate` datetime DEFAULT NULL,
PRIMARY KEY (`id`)
);
INSERT INTO events VALUES
(1 ,'Not in scope','2012-05-23'),
(3 ,'Test 0', '2014-05-09'),
(4 ,'Test 1', '2014-05-10'),
(5 ,'Test 2', '2014-05-11'),
(6 ,'Test 3', '2014-05-12'),
(7 ,'Test 4', '2014-05-13');
SELECT * FROM results;
+----+------------+--------+-------+-------+
| id | discipline | member | event | value |
+----+------------+--------+-------+-------+
| 1 | 1 | 2 | 4 | 10 |
| 2 | 1 | 1 | 4 | 8 |
| 3 | 1 | 2 | 5 | 9 |
| 4 | 2 | 3 | 5 | 9 |
| 5 | 1 | 2 | 6 | 11 |
| 6 | 1 | 2 | 7 | 11 |
| 7 | 1 | 2 | 1 | 11 |
| 8 | 1 | 2 | 3 | 7 |
+----+------------+--------+-------+-------+
SELECT * FROM events;
+----+--------------+---------------------+
| id | name | startDate |
+----+--------------+---------------------+
| 1 | Not in scope | 2012-05-23 00:00:00 |
| 3 | Test 0 | 2014-05-09 00:00:00 |
| 4 | Test 1 | 2014-05-10 00:00:00 |
| 5 | Test 2 | 2014-05-11 00:00:00 |
| 6 | Test 3 | 2014-05-12 00:00:00 |
| 7 | Test 4 | 2014-05-13 00:00:00 |
+----+--------------+---------------------+
Result should be:
+---------+------------+--------+-------+-------+
| id | discipline | member | event | value |
+---------+------------+--------+-------+-------+
| 3 | 1 | 1 | 4 | 8 |
| 5 | 1 | 2 | 6 | 11 |
+---------+------------+--------+-------+-------+
My first approach was to group by member id, but it's not that easy. So I tried a lot of different approaches from the web and from my colleages.
The last one was:
select res.*
from `results` as res
join (select id, max(value)
from results
join events on results.event = events.id
where discipline = 1
events.name like 'Test%'
Group by id
Order by events.startDate ASC) as tmpRes
on res.id = tmpRes.id
group by member
order by value DESC
But the result in this example would be a random result id for member 2.

Answer 1

Should be correct now, but let me know if there's a mistake...
SELECT r.*
FROM events e
JOIN results r
ON r.event = e.id
JOIN
( SELECT r.member
, MIN(e.startdate) min_startdate
FROM events e
JOIN results r
ON r.event = e.id
JOIN
( SELECT member
, MAX(value) max_value
, discipline
FROM events e
JOIN results r
ON r.event = e.id
WHERE discipline = 1
AND name LIKE 'Test%'
GROUP
BY member
) x
ON x.member = r.member
AND x.max_value = r.value
AND x.discipline = r.discipline
AND e.name LIKE 'Test%'
GROUP
BY member
) y
ON y.member = r.member
AND y.min_startdate = e.startdate;
Although fast, because these queries can get rather complex and cumbersome, there's an undocumented hack that achieves the same result. It goes something like this...
SELECT *
FROM
( SELECT r.*
FROM events e
JOIN results r
ON r.event = e.id
WHERE discipline = 1
AND name LIKE 'Test%'
ORDER
BY member
, value DESC
, startdate
) x
GROUP
BY member;

Answer 2

If I understand your question correctly, you need to group on member in the sub-query. Try the following:
select res.*
from `results` as res
join (select member, min(event) AS minEvent, max(value) AS maxValue
from results
where discipline = 1
Group by member) as tmpRes
on res.member = tmpRes.member AND res.event=tmpRes.minEvent AND res.value=tmpRes.maxValue
order by res.value
EDIT (bast on most recent comment): If that's the case, you'll need to join on the Events table. Unless the startDate field is actually a temporal field, it's going to be a big mess.
It would have made things easier with all the requirements included in the original question.