MYSQL GROUP BY on 2 Tables with MAX - mysql

Question

I have 2 mysql tables:
record table:
and
race table:
I want to select the records from the 1st table group by id_Race but only the MAX from column "secs".
I tried the following but didnt work:
$query = "SELECT rec.RecordsID,rec.id_Athlete,rec.date_record,rec.id_Race,rec.placeevent,rec.mins,rec.secs,rec.huns,rec.distance,rec.records_text,r.name,MAX(rec.secs)
FROM records AS rec INNER JOIN race AS r ON r.RaceID=rec.id_Race WHERE (id_Athlete=$u_athlete) GROUP BY rec.id_Race;";
($u_athlete is a variable i get from _SESSION)
Can you help me about that?
Thank you.

Answer 1

When you use an aggregation function like MAX and select all fields, you are forced to include all selected fields that are not affected by the MAX inside the GROUP BY clause.
Though you can use a window function like ROW_NUMBER that will group by specifically on id_Race and order by the secs column in a descendent way (so that the highest value of secs will be associated with row_number=1).
Afterwards you can select the rows which have row_number=1 and the id_Athlete you pass using the variable.
SELECT
rec.RecordsID,
rec.id_Athlete,
rec.date_record,
rec.id_Race,
rec.placeevent,
rec.mins,
rec.secs,
rec.huns,
rec.distance,
rec.records_text,
race.name,
FROM
(
SELECT
*,
ROW_NUMBER() OVER(PARTITION BY id_race ORDER BY secs) rank
FROM
record
) rec
INNER JOIN
race race
ON
race.RaceID=rec.id_Race
WHERE
rec.rank = 1
AND
rec.id_Athlete = $u_athlete;