從其他計算字段中計算出的Mysql歸檔

Question

我尋求一種方法來寫這樣的東西

select complicated_calculation1 as comp1, 
complicated_calculation2 as comp2, 
(comp1/comp2) as percent
from table

而不是像這樣復雜得多

select complicated_calculation1 as comp1, 
complicated_calculation2 as comp2, 
(complicated_calculation1/complicated_calculation2) as percent
from table

這可能嗎？

Answer 1

不在同一行。

您可以做的是：

SELECT comp1, comp2, (comp1/comp2) as percent FROM(
select complicated_calculation1 as comp1, 
complicated_calculation2 as comp2
from table) AS t

Answer 2

no u cann't use this 

select complicated_calculation1 as comp1, 
complicated_calculation2 as comp2, 
(comp1/comp2) as percent
from table

u have to use only this 

select complicated_calculation1 as comp1, 
complicated_calculation2 as comp2, 
(complicated_calculation1/complicated_calculation2) as percent
from table

because rantime calculation can not be applied on Alis field name