在SQL SELECT中找到COUNT个最大值

Question

I have SQL table information of runs like time, distance, pace ... I would like to have information of the best maximum runned distance by the month by user. I need to COUNT runned distance by every month and find the best one (MAX).

My table looks like this:

+----+--------+--------+----------+
| ID | USERID | MONTH  | DISTANCE |
+----+--------+--------+----------+
| 1  |    1   | 201707 |   6.69   |
+----+--------+--------+----------+
| 2  |    2   | 201707 |   6.03   |
+----+--------+--------+----------+
| 3  |    2   | 201707 |   6.02   |
+----+--------+--------+----------+
| 4  |    1   | 201706 |   7.25   |
+----+--------+--------+----------+
| 5  |    1   | 201706 |   7.13   |
+----+--------+--------+----------+
| 6  |    2   | 201705 |   7.03   |
+----+--------+--------+----------+
| 7  |    3   | 201705 |   6.31   |
+----+--------+--------+----------+
| 8  |    1   | 201705 |   5.28   |
+----+--------+--------+----------+
| 9  |    1   | 201704 |   4.44   |
+----+--------+--------+----------+
| 10 |    2   | 201704 |   5.94   |
+----+--------+--------+----------+

I try this but I have no output:

$select3run = mysqli_query($conn, "SELECT month, MAX(mycount) FROM (SELECT month, SUM(distance) AS mycount FROM runbeh GROUP BY month, distance) a GROUP BY month");
while($data=mysqli_fetch_array($select3run)) {
$max=$data['mycount'];
}

echo $max;

Have no more idea how to find value I'm looking for. Can somebody help me?

Answer 1

You should use a proper alias for the column name eg: my_max

    $select3run = mysqli_query($conn, "
        SELECT month, MAX(mycount)  as my_max
        FROM (SELECT month, SUM(distance) AS mycount 
        FROM runbeh GROUP BY month, distance) a 
        GROUP BY month");
    while($data=mysqli_fetch_array($select3run)) {
      $max=$data['my_max'];
    }

    echo $max;

Answer 2

Example:

http://sqlfiddle.com/#!9/29009f/8

SQL:

SELECT r.userid, r.month, max(r.sumdistance) 
FROM
(
  SELECT userid, month, sum(distance) as sumdistance 
  FROM runners 
  GROUP BY month, userid
) as r 
GROUP BY r.userid

Answer 3

SOLVED!

Many thanks to Raimondas Kazlauskas and scaisEdge whos show me the way and help me.

Working code for show most distance runned per month by users:

$select3run = mysqli_query($conn, "SELECT month, MAX(mycount)  as my_max 
FROM
(SELECT month, SUM(distance) AS mycount FROM runners GROUP BY month) a GROUP 
BY mycount DESC LIMIT 1");
while($data=mysqli_fetch_array($select3run)) {
$max=$data['my_max'];
echo $max; }

Where $max is the biggest SUM of distance which was runned by one month by user.

Answer 4

You should Try this one :-

Best run by every month of every user :-

select max(distance) AS MaxDistance,userid from runbeh group by month,userid

Note :- Never put any aggregate function in Group BY clause