如何在sql中按順序使用avg

Question

嗨，我剛剛接觸sql，並且遇到了這個問題。 我按平均分數的升序和合格率的降序對錶格子碼進行排序。 和代碼是

select * 
from subjcode 
group by sno 
order by(select avg(score) from subjcode group by sno)asc ; 

，它從來沒有做過這alwats說，錯誤碼：1242。

下表名爲subjcode：

Sno  cno  score 
S001 C001 78.90 
S001 C002 82.90 
S001 C003 59.00 
S002 C001 80.90 
S002 C002 72.90 
S003 C001 81.90 
S003 C002 81.90 
S004 C001 60.90 

請有人可以幫助我感謝

Answer 1

你並不需要把AVG()在另一個SELECT。剛：

ORDER BY AVG(score) 

但它沒有意義使用SELECT *當你分組。所有其他列將從組中的隨機行中選擇。你應該這樣做：

SELECT sno, AVG(score) AS avg 
FROM subjcode 
GROUP BY sno 
ORDER BY avg