Question

有没有办法将LIMIT设置为等于COUNT个DISTINCT条目？我有以下查询，但它只能LIMIT。我的表格会有DISTINCT个系列ID的变化，我希望每个Distinct系列ID中最后一集的最后一集。

SELECT t1.* FROM myTable.SeriesEpisodes t1 JOIN (SELECT seriesID, MAX(Season) Season FROM myTable.SeriesEpisodes GROUP BY seriesID) t2 ON t1.Season = t2.Season AND t1.seriesID = t2.seriesID ORDER BY Episode DESC LIMIT ???

我尝试过像下面这样的子查询，但是出错了。

LIMIT (SELECT COUNT(DISTINCT seriesID) FROM myTable.SeriesEpisodes)

Answer 1

此查询可能会返回您指定的结果。内联视图t2返回每个系列的最大季节。内联视图t3返回每个系列的每个季节的最大剧集。内联视图（派生表）的结果可以连接到原始表，以检索与这些最大值关联的详细信息行。（这假设(Series,Season,Episode)元组是唯一的。）

SELECT t1.*
  FROM myTable.SeriesEpisodes t1
  JOIN ( SELECT s2.Series
              , MAX(s2.Season) AS Season
           FROM myTable.SeriesEpisodes s2
          GROUP
             BY s2.Series
       ) t2
    ON t2.Series  = t1.Series
   AND t2.Season  = t1.Season
  JOIN ( SELECT s3.Series
              , s3.Season
              , MAX(s3.Episode) AS Episode
           FROM myTable.SeriesEpisodes s3
          GROUP
             BY s3.Series
              , s3.Season
       ) t3
    ON t3.Series  = t1.Series
   AND t3.Season  = t1.Season
   AND t3.Episode = t1.Episode
 ORDER 
    BY t1.Series
     , t1.Season

修改

- 或 -

可以使用这样的查询返回等效结果。内联视图t2返回每个系列的最新季节的最新剧集。

SELECT t1.* FROM myTable.SeriesEpisodes t1 JOIN ( SELECT s2.Series , s2.Season , MAX(s2.Episode) AS Episode FROM myTable.SeriesEpisodes s2 JOIN ( SELECT s3.Series , MAX(s3.Season) AS Season FROM myTable.SeriesEpisodes s3 GROUP BY s3.Series ) t3 ON t3.Series = s2.Series AND t3.Season = s2.Season GROUP BY s2.Series , s2.Season ) t2 ON t2.Series = t1.Series AND t2.Season = t1.Season AND t2.Episode = t1.Episode ORDER BY t1.Series , t1.Season

DISTINCT行的COUNT上的MYSQL LIMIT

1 个答案: