Question

我一直在使用HansUp给我的以下代码（干杯！），它一直很好用：

SELECT g.ID, Count(t.Grade) AS Total
FROM grade AS g 
LEFT JOIN (SELECT Grade FROM telephony WHERE [Date] BETWEEN #08/16/2010# AND #08/20/2010#) AS t ON g.ID=t.Grade 
GROUP BY g.ID 
ORDER BY 2 DESC;

我现在正在寻找返回的TOP 5结果。我认为它会如此简单：

SELECT **TOP 5** g.ID, Count(t.Grade) AS Total
FROM grade AS g 
LEFT JOIN (SELECT Grade FROM telephony WHERE [Date] BETWEEN #08/16/2010# AND #08/20/2010#) AS t ON g.ID=t.Grade 
GROUP BY g.ID 
ORDER BY 2 DESC;

不幸的是，这不起作用。

有没有人有任何想法。

由于

Answer 1

TOP子句将根据您的第一个排序字段为您提供顶级。由于您的第一个排序字段是所有记录的常量（2），因此您将获得所有记录。将ID字段添加到ORDER BY子句中，您将只获得五个记录。

SELECT TOP 5 g.ID, Count(t.Grade) AS Total
FROM grade AS g LEFT JOIN (SELECT Grade FROM telephony WHERE [Date] BETWEEN #08/16/2010# AND #08/20/2010#)  AS t ON g.ID = t.Grade
GROUP BY g.ID
ORDER BY g.ID, 2 DESC;

如果您实际上按降序排在前5位，请将SQL更改为以下内容：

SELECT TOP 5 g.ID, Count(t.Grade) AS Total
FROM grade AS g LEFT JOIN (SELECT Grade FROM telephony WHERE [Date] BETWEEN #08/16/2010# AND #08/20/2010#)  AS t ON g.ID = t.Grade
GROUP BY g.ID
ORDER BY Count(t.Grade) DESC , 2 DESC;

这是最重要的值，因此如果多个记录的总数相同且恰好位于Total的前5个值中，那么您将全部返回。如果你真的只想要五条记录，你必须对一个独特的字段进行排序。

Answer 2

这应该有用。

SELECT TOP 5 g.ID, Count(t.Grade) AS Total
FROM grade AS g 
LEFT JOIN (SELECT Grade FROM telephony WHERE [Date] BETWEEN #08/16/2010# AND #08/20/2010#) AS t ON g.ID=t.Grade 
GROUP BY g.ID 
ORDER BY 2 DESC

Answer 3

据我所知，这应该有效：

  SELECT TOP 5 g.ID, Count(t.Grade) AS Total
  FROM grade AS g 
  LEFT JOIN (SELECT Grade FROM telephony WHERE [Date] BETWEEN #08/16/2010# AND #08/20/2010#) AS t ON g.ID=t.Grade 
  GROUP BY g.ID 
  ORDER BY Count(t.Grade) DESC;

这里的关键点是，当您想在WHERE或ORDER BY子句中使用它时，可以使用SELECT语句中的完整表达式。

如果您只是使用Access查询网格来编写SQL，那么您可以立即获得正确的结果（尽管您必须深入SQL视图来编写子查询）。

使用带有COUNT和LEFT JOIN的TOP 5

3 个答案: