SQL平均總是返回0

Question

我有一個簡單的SQL命令：

SELECT Avg('observations1') AS AvgFeedback,
       Avg('observations2') AS AvgChallenge,
       Avg('observations3') AS AvgTalk,
       Avg('observations4') AS AvgSkills,
       Avg('observations5') AS AvgExpectations
FROM   .observations
WHERE  obsschool = 'admin';  

但是，當每個字段中都有數字時，每個結果均為0。 我究竟做錯了什么？ 謝謝。

Answer 1

刪除包含您的字段名稱的引號（ ' ）：

SELECT Avg(observations1) AS AvgFeedback,
       Avg(observations2) AS AvgChallenge,
       Avg(observations3) AS AvgTalk,
       Avg(observations4) AS AvgSkills,
       Avg(observations5) AS AvgExpectations
FROM   observations
WHERE  obsschool = 'admin'; 

傳遞字段名稱時，無需引號。

Answer 2

您可以嘗試一下，看看會得到什么結果嗎：

avg(cast(observations1 as dec(7,5))) as AvgFeedback