如何获得列值不等于零的平均值？

Question

我有一个问题

Select AVG(((cast(c.rating1 as Float)+ cast(c.rating2 as Float)+cast (c.rating3 as Float)+cast(c.rating4 as Float)+cast(c.rating5 as Float))/5))
From CSEReduxResponses c
Where 
     c.execoffice_date BETWEEN DATEADD(MONTH, DATEDIFF(MONTH, 0, @today)-1, 0)
AND DATEADD(MONTH, DATEDIFF(MONTH, -1, @today)-1, -1)
AND c.execoffice_status =1
AND C.rating1 <> 0 AND C.rating2 <> 0 AND C.rating3 <> 0 AND C.rating4 <> 0 AND 
C.rating5 <> 0

我得到了 1-5 的平均评分，但我也计算了等于“0”的评分。

我怎样才能让它只计算 rating[x] 不等于 '0' 的评级？ 它仍然会计数，但除了将其除以 5 之外，它将除以有多少列不是“0”。

我创建了一个http://sqlfiddle.com/#!3/570fa/7>

Answer 1

这不漂亮但应该可以：

  SELECT AVG((... SUM of 5 ratings ...) /
           (CASE WHEN rating1 > 0 THEN 1 ELSE 0 END + 
            CASE WHEN rating2 > 0 THEN 1 ELSE 0 END +
            CASE WHEN rating3 > 0 THEN 1 ELSE 0 END +
            CASE WHEN rating4 > 0 THEN 1 ELSE 0 END +
            CASE WHEN rating5 > 0 THEN 1 ELSE 0 END))
  FROM ...
  WHERE ...

做完这样的事情后，应该对数据规范化感到赞赏。

Answer 2

尝试使用VALUES 获取每行非 0 值的平均值。

SELECT
(
    SELECT AVG(rating)
    FROM (VALUES 
        (cast(c.rating1 as Float)), 
        (cast(c.rating2 as Float)), 
        (cast(c.rating3 as Float)), 
        (cast(c.rating4 as Float)), 
        (cast(c.rating5 as Float))
    ) AS v(rating)
    WHERE v.rating <> 0
) avg_rating
From CSEReduxResponses c
Where 
     c.execoffice_date BETWEEN DATEADD(MONTH, DATEDIFF(MONTH, 0, @today)-1, 0)
AND DATEADD(MONTH, DATEDIFF(MONTH, -1, @today)-1, -1)
AND c.execoffice_status = 1

http://sqlfiddle.com/#!3/570fa/26

我从您的WHERE 中删除了以下条件

AND C.rating1 <> 0 AND C.rating2 <> 0 AND C.rating3 <> 0 AND C.rating4 <> 0 AND 
C.rating5 <> 0

因为如果你把它留在里面，你只会计算有 5 个非 0 评级的行的平均值，我猜这不是你的意图。

要获得所有行中非 0 评分的平均值，请将所有非 0 评分的总和除以非 0 评分的总数。

SELECT
    CAST(SUM(sum_rating) as float)/SUM(count_rating)
From CSEReduxResponses c
CROSS APPLY (
    SELECT SUM(rating), COUNT(rating)
    FROM (VALUES 
        (c.rating1), 
        (c.rating2), 
        (c.rating3), 
        (c.rating4), 
        (c.rating5)
    ) AS v(rating)
    WHERE v.rating <> 0
) AS x (sum_rating, count_rating)
Where 
    c.execoffice_date BETWEEN DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE())-1, 0)
AND DATEADD(MONTH, DATEDIFF(MONTH, -1, GETDATE())-1, -1)
AND c.execoffice_status = 1

http://sqlfiddle.com/#!3/570fa/35

正如其他人所提到的，如果可能，您应该考虑规范化您的表格。