关于 sqlzoo SQL 的问题

[rabbbit]

sqlzoo 第 12 题, 查找某演员出演电影次数最多的年份 https://sqlzoo.net/wiki/More_JOIN_operations/zh

我这么写对吗?为啥答案搞的这么绕,性能更好吗,还是为了用 join 而用?

这是我写的

select yr, count(*) as c from movie
where id in (
  select movieid from casting 
  where actorid=(select id from actor where name='John Travolta')
)
group by yr order by c desc limit 1

这是答案

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
)