t, MySQL - rextester

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DROP TABLE IF EXISTS tourney_players;
DROP TABLE IF EXISTS results;

CREATE TABLE tourney_players
    (`tp_id` int, `resultid` int, `tourneyid` int)
;
    
INSERT INTO tourney_players
    (`tp_id`, `resultid`, `tourneyid`)
VALUES
    (1, 2, 91),
    (2, 21, 91),
    (3, 29, 91),
    (4, 1, 91),
    (5, 3, 92)
;

CREATE TABLE results
    (`r_id` int, `day1_best` int)
;
    
INSERT INTO results
    (`r_id`, `day1_best`)
VALUES
    (1, 3),
    (2, 1),
    (3, 4),
    (21, 1),
    (29, 2)
;

SELECT *
FROM tourney_players t
JOIN results r
  ON t.`resultid` = r.`r_id`;
  
SELECT `tourneyid`, `day1_best`, count(*) as total
FROM tourney_players t
JOIN results r
  ON t.`resultid` = r.`r_id`
GROUP BY `tourneyid`, `day1_best`;

SELECT t.`tp_id`, r.`r_id`, r.`day1_best`
FROM tourney_players t
JOIN results r
  ON t.`resultid` = r.`r_id`
LEFT JOIN (SELECT `tourneyid`, `day1_best`, count(*) as total
           FROM tourney_players t
           JOIN results r
             ON t.`resultid` = r.`r_id`
           GROUP BY `tourneyid`, `day1_best`
           HAVING count(*) > 1) as filter           
  ON t.`tourneyid` = filter.`tourneyid`
 AND r.`day1_best` = filter.`day1_best`
WHERE filter.`tourneyid` IS NOT NULL;


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