항상 충실하게

SELECT 
    x,
    y,
    z,
    CASE
        WHEN x + y > z AND x + z > y AND y + z > x THEN 'Yes'
        ELSE 'No'
    END AS 'triangle'
FROM
    triangle
;

SELECT bb.name as name FROM (SELECT count(id) as vv, candidateId FROM Vote Group BY candidateId Order By vv desc limit 1) aa  JOIN Candidate bb on aa.candidateId = bb.id

SELECT cc.name as name FROM (SELECT count(id) as cnt, managerId FROM Employee GROUP BY managerId having cnt>=5) bb JOIN Employee cc ON cc.id = bb.managerId

```

SELECT ROUND(COUNT(t2.player_id)/COUNT(t1.player_id),2) AS fraction
FROM
(SELECT player_id, MIN(event_date) AS first_login FROM Activity GROUP BY player_id) t1 LEFT JOIN Activity t2
ON t1.player_id = t2.player_id AND t1.first_login = t2.event_date - 1

```