mysql - 根据别名 : SQL 进行划分

Question

希望将“返回”列和“总计”列分开，以获得最多返回产品的返回率。这是我所拥有的，如何在别名上添加除法函数？

SELECT brand
    ,model
    ,count(*) Total
    ,sum(case when returned = 'Y' then 1 else 0 end) as Returned
    ,sum(case when returned = '' then 1 else 0 end) as Kept

FROM table
WHERE year= '2018'
AND NOT type = 's'
GROUP by model

ORDER by Returned DESC;

谢谢

Answer 1

您可以将其包装在另一个SELECT中

SELECT brand
    ,model
    ,count(*) Total
    ,sum(case when returned = 'Y' then 1 else 0 end) as Returned
    ,sum(case when returned = '' then 1 else 0 end) as Kept
    ,(SELECT Returned/Total) as Rate
FROM table
WHERE year= '2018'
AND NOT type = 's'
GROUP by model
ORDER by Returned DESC;