mysql：某些数据的总和除以同一表中总数据的总和

Question

date   value 
    2012-01-01  124 
    2012-01-02  250 
    2012-04-21  56 
    2012-07-06  198 
    2012-09-24  650 
    2013-07-07 1000 

我想将2012-01-01到2012-07-06的值“求和”，再除以“sum “从2012-01-01到2013-07-07的总数在同一个表中。

Answer 1

SELECT (SELECT SUM(value) FROM yourTable WHERE date BETWEEN '2012-01-01' AND '2012-07-06')/
     (SELECT SUM(value) FROM yourTable WHERE date BETWEEN '2012-01-01' AND '2013-07-07') 

或：

SELECT SUM(IF(date BETWEEN '2012-01-01' AND '2012-07-06'), value, 0))/
     SUM(IF(date BETWEEN '2012-01-01' AND '2013-07-07'), value, 0)) 
FROM yourTable 

Answer 2

Select sum(if(date between ... and ..., value, 0)/sum(value) 
from table where date beteen ... and ... 

使用在其中条件较小的日期范围在如果（），越宽。