Mysql 最有效的写条件的方法

我目前正在完成sqlzoo的教程，并遇到以下代码作为#12的答案：

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难道没有更简洁的方式来表达这段代码吗

是的。如果我能正确理解这个问题，它会简单得多

SELECT yr,COUNT(title) 
   FROM movie JOIN casting ON movie.id=movieid
        JOIN 
        actor   ON actorid=actor.id
WHERE name='John Travolta'
GROUP BY yr
HAVING COUNT(title) > 2 

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看起来原始站点的建议答案与他们提出的问题不匹配

对他们提出的问题的最佳答案是：

SELECT yr,COUNT(title) FROM
  movie JOIN casting ON movie.id=movieid
         JOIN actor   ON actorid=actor.id
WHERE name='John Travolta'
GROUP BY yr
HAVING COUNT(title)>2

他们的回答是：

SELECT yr,COUNT(title) FROM
movie JOIN casting ON movie.id=movieid
JOIN actor ON actorid=actor.id
WHERE name='John Travolta'
GROUP BY yr
HAVING COUNT(title)=
(SELECT MAX(c) FROM (SELECT yr,COUNT(title) AS c 
FROM movie 
JOIN casting ON movie.id=movieid JOIN actor ON actorid=actor.id
WHERE name='John Travolta'
GROUP BY yr) AS t

)

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但这实际上回答了一个不同的问题，那就是：“他拍电影最多的那一年是哪一年，他拍了多少部电影？”

“他拍了两部以上电影的那一年。”所以

有COUNT（title）>2

SELECT yr,COUNT(title) FROM
movie JOIN casting ON movie.id=movieid
JOIN actor ON actorid=actor.id
WHERE name='John Travolta'
GROUP BY yr
HAVING COUNT(title)=
(SELECT MAX(c) FROM (SELECT yr,COUNT(title) AS c 
FROM movie 
JOIN casting ON movie.id=movieid JOIN actor ON actorid=actor.id
WHERE name='John Travolta'
GROUP BY yr) AS t