Question

任何人都可以帮助我，如果我输入“ GROUP BY DATE”，为什么该代码不起作用

DATE的样本值为201810、201811、201812、201901等

如果我删除“ GROUP BY DATE”，则它的工作将对所有行求和我想要按日期列出所有省份的SUM totaluser组，有什么想法吗？

SELECT DATE AS dates,
   parProvinces.id AS provinceId, 
   parProvinces.name AS province,   
   sum(totaluser) AS countUser,     
   ( SELECT 
         SUM(totalUser)         
         FROM dsMonthlyDemographies         
         GROUP BY DATE  // <<<<-- this is didn't
   ) AS totalUserPerMonths

FROM dsMonthlyDemographies, parProvinces 
WHERE (provincesId = parProvinces.id) 
GROUP BY provinceId, dates 
ORDER BY dates ASC, provinceId ASC

消息错误：

错误代码：1242 子查询返回1行以上

更新

这是dsMonthlyDemographies的示例数据

表parProvinces

Answer 1

您需要一个标量子查询

SELECT DATE AS dates,
   parProvinces.id AS provinceId, 
   parProvinces.name AS province,   
   sum(totaluser) AS countUser,     
   ( SELECT 
         SUM(totalUser)         
         FROM dsMonthlyDemographies b where a.date=b.date        
   ) AS totalUserPerMonths

FROM dsMonthlyDemographies a join parProvinces on a.provincesId = parProvinces.id
GROUP BY provinceId, dates 
ORDER BY dates ASC, provinceId ASC

OR

select * from 
(SELECT DATE AS dates,
   parProvinces.id AS provinceId, 
   parProvinces.name AS province,   
   sum(totaluser) AS countUser     
   FROM dsMonthlyDemographies a join parProvinces on a.provincesId =parProvinces.id
   GROUP BY provinceId, dates 
)A inner join 
( SELECT 
         dates,SUM(totalUser)         
         FROM dsMonthlyDemographies group by dates   
 ) AS B on A.dates=b.dates

注意：最好总是使用显式联接，而不是用逗号分隔的联接

Answer 2

您的朋友，您只需添加b.provincesId = dsMonthlyDemographies.provincesId，如下所示：

SELECT DATE AS dates,
   parProvinces.id AS provinceId, 
   parProvinces.name AS province,   
   sum(totaluser) AS countUser,     
   ( SELECT 
         SUM(b.totalUser)         
         FROM dsMonthlyDemographies  b       
         b.provincesId = dsMonthlyDemographies.provincesId
   ) AS totalUserPerMonths


    FROM dsMonthlyDemographies, parProvinces 
    WHERE (provincesId = parProvinces.id) 
    GROUP BY provinceId, dates 
    ORDER BY dates ASC, provinceId ASC

如何确定来自不同组的总和除以

2 个答案: