内部联接两个表，仅显示最新记录（mySQL）

Question

I have two parent tables which create a composite inside the child table (compresults)

I want to get the most recent record (only 1) for each athlete

I know the answer is along the lines of selecting the competition with the max date and only displaying it that way, however i have been trying to do this but i cannot get the formatting right

Parent Table (athletes) +---------+-------+ | athlete | name | +---------+-------+ | 1 | James | | 2 | Gemma | +---------+-------+ +---------+-------+ | athlete | name | +---------+-------+ | 1 | James | | 2 | Gemma | +---------+-------+

Parent Table (competitions) +-----+----------+----------+ | cid | compname | compdate | +-----+----------+----------+ | 1 | Comp A | 2015 | | 2 | Comp B | 2014 | +-----+----------+----------+ +-----+----------+----------+ | cid | compname | compdate | +-----+----------+----------+ | 1 | Comp A | 2015 | | 2 | Comp B | 2014 | +-----+----------+----------+

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

EXPECTED RESULT: +-------+----------+--------+ | name | compname | result | +-------+----------+--------+ | James | Comp A | 500 | | Gemma | Comp B | 450 | +-------+----------+--------+ +-------+----------+--------+ | name | compname | result | +-------+----------+--------+ | James | Comp A | 500 | | Gemma | Comp B | 450 | +-------+----------+--------+

Any Idea? Thanks!

Answer 1

try using

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

I believe this receives the result you're after.

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
                    )