内部联接两个表，仅显示最新记录（mySQL）

Question

我有两个父表，它们在子表中创建一个复合表（结果）

我想获取每位运动员的最新记录（仅1条）

我知道答案是按照选择最大日期的比赛并仅以这种方式显示的，但是我一直在尝试这样做，但是我无法正确设置格式

父表（运动员） +---------+-------+ | athlete | name | +---------+-------+ | 1 | James | | 2 | Gemma | +---------+-------+ +---------+-------+ | athlete | name | +---------+-------+ | 1 | James | | 2 | Gemma | +---------+-------+

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

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

预期结果： +-------+----------+--------+ | name | compname | result | +-------+----------+--------+ | James | Comp A | 500 | | Gemma | Comp B | 450 | +-------+----------+--------+ +-------+----------+--------+ | name | compname | result | +-------+----------+--------+ | James | Comp A | 500 | | Gemma | Comp B | 450 | +-------+----------+--------+

任何想法？ 谢谢！

Answer 1

尝试使用

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

Answer 2

我相信这会收到您追求的结果。

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
                    )