Question

I have the following MySQL tables (Simplified)

DRIVER (D)
----------
id (PK)
name

RACE (RA)
---------
id (PK)
date

RESULT (RE)
-----------
id (PK)
raceid (FK -> RACE.id)
driverid (FK -> DRIVER.id)
bestRound
averageRound

I want to be able to list all drivers with their numRaces, firstRace, lastRace, bestRound, bestAverageRound and the dates on which their bestRound and bestAverageRound happened. I’m having problems with the last two, the dates for bestRound and bestAverageRound.

This is what I have so far:

SELECT D.name, COUNT(DISTINCT RE.raceid) AS numRaces, min(RA.date) AS firstRace,
max(RA.date) AS lastRace, min(RE.bestRound) AS bestRound,
min(RE.averageRound) AS bestAverageRound 
FROM DRIVER D
JOIN RESULT RE ON RE.driverid = D.id
JOIN RACE RA ON RA.id = RE.raceid
GROUP BY D.id
ORDER BY D.name

This is working correctly. But how do I proceed to select the dates from the RACE table on which the bestRound and bestAverageRound occurred? Thanks for your time.

Answer 1

Try this solution:

SELECT 
    a.*, b.date AS bestRoundDate, c.date AS bestAverageRoundDate
FROM
(
    SELECT 
        d.id, 
        d.name,
        COUNT(DISTINCT re.raceid) AS numRaces,
        MIN(ra.date) AS firstRace,
        MAX(ra.date) AS lastRace,
        MIN(re.bestRound) AS bestRound,
        MIN(re.averageRound) AS bestAverageRound
    FROM driver d
    INNER JOIN result re ON d.id = re.driverid
    INNER JOIN race ra ON re.raceid = ra.id
    GROUP BY d.id, d.name
) a
INNER JOIN
(
    SELECT aa.driverid, aa.bestRound, bb.date
    FROM result aa
    INNER JOIN race bb ON aa.raceid = bb.id
) b ON a.id = b.driverid AND a.bestRound = b.bestRound
INNER JOIN
(
    SELECT aa.driverid, aa.bestAverageRound, bb.date
    FROM result aa
    INNER JOIN race bb ON aa.raceid = bb.id
) c ON a.id = c.driverid AND a.bestAverageRound = c.bestAverageRound
ORDER BY
    a.name