Du bør lede efter dette:
Her udelader vi key record values (date + name)
de matcher i et skæringspunkt mellem key record values (date + name) who played football
og key record values (date + name) who did not play football
SELECT
p1.*
FROM
player p1
LEFT JOIN
(SELECT
pnfb.*
FROM
(SELECT
date, name
FROM
player
WHERE
sport <> 'football') pnfb
JOIN (SELECT
date, name
FROM
player
WHERE
sport = 'football') pfb ON (pnfb.date = pfb.date
AND pnfb.name = pfb.name)) p2 ON (p1.date = p2.date AND p1.name = p2.name)
WHERE
p2.date IS NULL;