尝试获取计数结果集的平均值

发布于 2024-12-09 16:18:25 字数 414 浏览 0 评论 0原文

我有以下 SQL:(bitemp)

SELECT COUNT (*) AS Count
  FROM Table T
 WHERE (T.Update_time =
           (SELECT MAX (B.Update_time )
              FROM Table B
             WHERE (B.Id = T.Id))
GROUP BY T.Grouping

现在我得到一个包含很多数字的结果集。我想得到这个列表的平均值。目前，我正在将列表导入Excel并使用其平均功能。但是DB2有一个AVG功能，但我没有让它工作。

我尝试了SELECT AVG(COUNT(*))和SELECT AVG(*) FROM (theQuery)。

原文

I have the following SQL:(bitemp)

SELECT COUNT (*) AS Count
  FROM Table T
 WHERE (T.Update_time =
           (SELECT MAX (B.Update_time )
              FROM Table B
             WHERE (B.Id = T.Id))
GROUP BY T.Grouping

now I am getting a resultset with a lot of numbers. I want to get the average of this list. At the moment, I am importing the list into excel and use its average function. But there is a AVG function for DB2, but I did not get it to work.

I tried SELECT AVG(COUNT(*)) and also SELECT AVG(*) FROM (theQuery).

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浪漫之都 2024-12-16 16:18:25

您只需将查询作为子查询：

SELECT avg(count)
  FROM 
    (
    SELECT COUNT (*) AS Count
      FROM Table T
     WHERE T.Update_time =
               (SELECT MAX (B.Update_time )
                  FROM Table B
                 WHERE (B.Id = T.Id))
    GROUP BY T.Grouping
    ) as counts

编辑：我认为这应该是相同的：

SELECT count(*) / count(distinct T.Grouping)
  FROM Table T
 WHERE T.Update_time =
           (SELECT MAX (B.Update_time)
              FROM Table B
             WHERE (B.Id = T.Id))

You just can put your query as a subquery:

SELECT avg(count)
  FROM 
    (
    SELECT COUNT (*) AS Count
      FROM Table T
     WHERE T.Update_time =
               (SELECT MAX (B.Update_time )
                  FROM Table B
                 WHERE (B.Id = T.Id))
    GROUP BY T.Grouping
    ) as counts

Edit: I think this should be the same:

SELECT count(*) / count(distinct T.Grouping)
  FROM Table T
 WHERE T.Update_time =
           (SELECT MAX (B.Update_time)
              FROM Table B
             WHERE (B.Id = T.Id))

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