我想要显示最高的号码。的剧集

Question

我有以下代码

SELECT PRESENTERS.PNRFNAME, PRESENTERS.PNRLNAME, 
COUNT(EPISODES.PRESENTERID) AS "no. of episodes"
FROM EPISODES
JOIN PRESENTERS
ON EPISODES.PRESENTERID=PRESENTERS.PRESENTERID
GROUP BY PRESENTERS.PNRFNAME, PRESENTERS.PNRLNAME
ORDER BY COUNT(EPISODES.PRESENTERID)

我尝试添加

HAVING COUNT(EPISODES.PRESENTERID) > 2 

但是我必须假装没有看到多少没有。有一集是在那里。还有其他方式我可以显示更多没有的行。一集？

Answer 1

如果您只想要具有最多剧集数量的行，您可以在查询结尾添加此项（并移除HAVING，这是无用的）：

ORDER BY `no. of episodes` DESC
LIMIT 1

这个想法：你对行进行排序，使得剧集最多的记录位于顶部，然后将结果限制为一定数量（此处为1）。

您错过的是DESC关键字，因为默认情况下按排序从低到高（ASC，升序）。

Answer 2

    select top 1 PRESENTERS.PNRFNAME, PRESENTERS.PNRLNAME,COUNT(EPISODES.PRESENTERID) AS "no. of episodes" FROM EPISODES JOIN PRESENTERS ON EPISODES.PRESENTERID=PRESENTERS.PRESENTERID GROUP BY PRESENTERS.PNRFNAME, PRESENTERS.PNRLNAME ORDER BY COUNT(EPISODES.PRESENTERID) desc;

Answer 3

您不需要having，只需要order by COUNT(EPISODES.PRESENTERID) DESC，这应该会让您从高到低

Answer 4

默认情况下，MySQL按升序对行进行排序。你需要明确告诉它按降序排序。

SELECT PRESENTERS.PNRFNAME, PRESENTERS.PNRLNAME, 
COUNT(EPISODES.PRESENTERID) AS "no. of episodes"
FROM EPISODES
JOIN PRESENTERS
ON EPISODES.PRESENTERID=PRESENTERS.PRESENTERID
GROUP BY PRESENTERS.PNRFNAME, PRESENTERS.PNRLNAME
ORDER BY COUNT(EPISODES.PRESENTERID) DESC;

上面会为您提供降序或下降的所有行，但如果您只想要一行episodes最多的行，则可以limit 1

SELECT PRESENTERS.PNRFNAME, PRESENTERS.PNRLNAME, 
COUNT(EPISODES.PRESENTERID) AS "no. of episodes"
FROM EPISODES
JOIN PRESENTERS
ON EPISODES.PRESENTERID=PRESENTERS.PRESENTERID
GROUP BY PRESENTERS.PNRFNAME, PRESENTERS.PNRLNAME
ORDER BY COUNT(EPISODES.PRESENTERID) DESC LIMIT 1;

Answer 5

只需将DESC附加到您当前的查询中即可！

SELECT        PRESENTERS.PNRFNAME, PRESENTERS.PNRLNAME, COUNT(EPISODES.PRESENTERID) AS [no. of episodes]
FROM            EPISODES INNER JOIN
                         PRESENTERS ON EPISODES.PRESENTERID = PRESENTERS.PRESENTERID
GROUP BY PRESENTERS.PNRFNAME, PRESENTERS.PNRLNAME
ORDER BY [no. of episodes] DESC

期望的输出：

选择Top 1：

SELECT        TOP (1) PRESENTERS.PNRFNAME, PRESENTERS.PNRLNAME, COUNT(EPISODES.PRESENTERID) AS [no. of episodes]
FROM            EPISODES INNER JOIN
                         PRESENTERS ON EPISODES.PRESENTERID = PRESENTERS.PRESENTERID
GROUP BY PRESENTERS.PNRFNAME, PRESENTERS.PNRLNAME
ORDER BY [no. of episodes] DESC