如何在MySQL中的另一列计算中重用动态列？

Question

我有这样的疑问：

SELECT 
  IF(daycode=1,(SELECT...),(SELECT...)) AS weekavg,
  (SELLOFF1 / weekavg) AS procent
FROM .....

它告诉我：Unknown column 'weekavg' in 'field list'，这是在我添加了除法之后发生的，之后就可以了。

Answer 1

您可以使用子查询：

SELECT (selloff1 / weekavg) AS procent
FROM (
  SELECT 
    selloff1, IF(daycode=1,(SELECT...),(SELECT...)) AS weekavg
  FROM ...
)