Question

我有一个关于如何将以下陈述分组为几个月的问题。
数据库是MYSQL

期望的结果是：

DRNAME, Jan, Feb, Mar, April, May ,June
SISHEN, 0, 0, 100, 250, 450, 500, 0

我得到的结果是：

DRNAME, Jan, Feb, Mar, April, May ,June
SISHEN, 0, 0, 100, 0, 0, 0,0
SISHEN, 0, 0,0,250,0,0,0
SISHEN, 0, 0, 0,0 , 450, 0, 0

查询是

select  drname,
case when month(loaddate) = 1 then sum(drvalue) end as 'Jan',<br>
case when month(loaddate) = 2 then sum(drvalue) end as 'Feb',<br>
case when month(loaddate) = 3 then sum(drvalue) end as 'March',<br>
case when  month(loaddate) = 4 then sum(drvalue) end as 'April',<br>
case when  month(loaddate) = 5 then sum(drvalue) end as 'May',<br>
case when  month(loaddate) = 6 then sum(drvalue) end as 'June'<br>
from tblloadschedule<br>
where cancelloadflag = 'N' and drname like 'sish%'<br>
group by drname,month(loaddate)

Answer 1

您需要从month(loaddate)子句中删除group by，然后使用条件聚合：

select drname, 
   sum(case when month(loaddate) = 1 then drvalue else 0 end) as 'Jan',
   sum(case when month(loaddate) = 2 then drvalue else 0 end) as 'Feb',
   sum(case when month(loaddate) = 3 then drvalue else 0 end) as 'March',
   sum(case when month(loaddate) = 4 then drvalue else 0 end) as 'April',
   sum(case when month(loaddate) = 5 then drvalue else 0 end) as 'May',
   sum(case when month(loaddate) = 6 then drvalue else 0 end) as 'June'
from tblloadschedule
where cancelloadflag = 'N' and drname like 'sish%'
group by drname

Answer 2

修改您的查询以获取条件CASE表达式的聚合：

SELECT
    drname,
    SUM(CASE WHEN MONTH(loaddate) = 1 THEN drvalue END) AS Jan,
    SUM(CASE WHEN MONTH(loaddate) = 2 THEN drvalue END) AS Feb,
    SUM(CASE WHEN MONTH(loaddate) = 3 THEN drvalue END) AS March,
    SUM(CASE WHEN MONTH(loaddate) = 4 THEN drvalue END) AS April,
    sum(CASE WHEN MONTH(loaddate) = 5 THEN drvalue END) AS May,
    sum(CASE WHEN MONTH(loaddate) = 6 THEN drvalue END) AS June
FROM tblloadschedule
WHERE
    cancelloadflag = 'N' AND drname LIKE 'sish%'
GROUP BY
    drname;

Answer 3

您不需要昂贵的案例：

select drname, 
   sum(if(month(loaddate) = 1 ,drvalue,0) as 'Jan',
   sum(if(month(loaddate) = 2 , drvalue ,0) as 'Feb',
   sum(if(month(loaddate) = 3 , drvalue ,0) as 'March',
   sum(if(month(loaddate) = 4 , drvalue ,0) as 'April',
   sum(if(month(loaddate) = 5 , drvalue ,0) as 'May',
   sum(if(month(loaddate) = 6 , drvalue ,0) as 'June'
from tblloadschedule
where cancelloadflag = 'N' and drname like 'sish%'
group by drname

不使用IF编辑：

select drname, 
   sum((month(loaddate) = 1 ) * drvalue) as 'Jan',
   sum((month(loaddate) = 2 ) * drvalue) as 'Feb',
   sum((month(loaddate) = 3 ) * drvalue) as 'March',
   sum((month(loaddate) = 4 ) * drvalue) as 'April',
   sum((month(loaddate) = 5 ) * drvalue) as 'May',
   sum((month(loaddate) = 6 ) * drvalue) as 'June'
from tblloadschedule
where cancelloadflag = 'N' and drname like 'sish%'
group by drname

Answer 4

来自A. Colonna和IF的方法在服务器上确实效率更高，并返回了预期的结果。

非常感谢所有评论的人我使用的代码是：选择drname，
   sum（（month（loaddate）= 1）* drvalue）为'Jan'，
   sum（（month（loaddate）= 2）* drvalue）为'Feb'，
   sum（（month（loaddate）= 3）* drvalue）为'March'，
   sum（（month（loaddate）= 4）* drvalue）为'April'，
   sum（（month（loaddate）= 5）* drvalue）为'May'，
   sum（（month（loaddate）= 6）* drvalue）为'June' 来自tblloadschedule
其中cancelloadflag ='N'
小组分组

按月汇总值，在mysql

4 个答案: