內部聯接兩個表，並只作最新記錄顯示（MySQL的）

Question

我有一個創建子表內複合（compresults）

兩個上級表我想獲得最新的每個記錄（只有1個）運動員

我知道答案是一起選擇具有最大日比賽，只顯示它這樣的線，但是我一直在努力這樣做，但我不能讓格式正確

父表（運動員） +---------+-------+ | athlete | name | +---------+-------+ | 1 | James | | 2 | Gemma | +---------+-------+

父表（比賽） +-----+----------+----------+ | cid | compname | compdate | +-----+----------+----------+ | 1 | Comp A | 2015 | | 2 | Comp B | 2014 | +-----+----------+----------+

子表（compresults） +---------+-----+--------+ | athlete | cid | result | +---------+-----+--------+ | 1 | 1 | 500 | | 1 | 2 | 550 | | 2 | 2 | 450 | +---------+-----+--------+

預期的結果： +-------+----------+--------+ | name | compname | result | +-------+----------+--------+ | James | Comp A | 500 | | Gemma | Comp B | 450 | +-------+----------+--------+

任何想法？謝謝！

Answer 1

我相信這收到你之後的結果。

SELECT a.`name`, b.`compname`, c.`result` 
FROM `compresults` c 
INNER JOIN `competitions` b ON b.cid = c.cid 
INNER JOIN `athletes` a ON c.`athlete` = a.`athlete` 
WHERE b.`compdate` = (
            SELECT co.`compdate` 
            FROM `competitions` co INNER JOIN `compresults` cr ON cr.`cid` = co.`cid` 
            WHERE cr.`athlete` = a.`athlete` 
            ORDER BY co.`compdate` DESC LIMIT 1 
        ) 

Answer 2

嘗試使用

select b.name,c.compname,a.result from compresults a left join athletes 
b on (a.athlete)=b.athlete 
left join competitions c on (a.cid)=c.cid