Question

我有一种情况，我需要在一个类别的时间段内订购一定数量的积分，然后进入前2，因为您只能计算一个时期内的两个最高点总数。目前我的查询看起来像这样，但它不起作用。目前只是在选择2之后对结果进行排序。

SELECT TOP 2 *
FROM player as p 
INNER JOIN  player_event as pe ON p.PID=pe.PID 
INNER JOIN event as e ON pe.EID=e.EID
WHERE e.ESeasonID=171801 AND e.ECat='Cup/Challenge'
ORDER BY pe.PEPts DESC

Answer 1

你可以使用限制2

来做到这一点

    SELECT  *
    FROM player as p 
    INNER JOIN  player_event as pe ON p.PID=pe.PID 
    INNER JOIN event as e ON pe.EID=e.EID
    WHERE e.ESeasonID=171801 AND e.ECat='Cup/Challenge'
    ORDER BY pe.PEPts DESC LIMIT 2;

Answer 2

结果集的排序通常发生在查询处理的最后。尝试使用窗口函数来获得所需内容：

SELECT *
FROM player as p 
INNER JOIN player_event as pe ON p.PID=pe.PID 
INNER JOIN event as e ON pe.EID=e.EID
WHERE e.ESeasonID=171801 AND e.ECat='Cup/Challenge'
QUALIFY ROW_NUMBER() OVER(ORDER BY pe.PEPts DESC) <=2

上面的查询应该适用于Teradata。如果您使用的是Postgres或其他不支持QUALIFY的系统，您可以尝试：

SELECT *
FROM (
  SELECT 
    p.*, pe.*, e.*,
    ROW_NUMBER() OVER(ORDER BY pe.PEPts DESC) AS RowNum
  FROM player as p 
  INNER JOIN player_event as pe ON p.PID=pe.PID 
  INNER JOIN event as e ON pe.EID=e.EID
  WHERE e.ESeasonID=171801 AND e.ECat='Cup/Challenge'
) src
WHERE RowNum <=2

ROW_NUMBER（）OVER（由pe.PEPts订购）为每一行分配一个＆＃34;行号＆＃34;基于（ORDER BY ...）中指定的顺序。 Teradata中的QUALIFY等同于WHERE子句，但仅适用于窗口函数。

Answer 3

此查询将根据本赛季的分数和所提供的类别为您提供前2名球员

syracuse

SQL - 订购结果后选择顶部

3 个答案: