Question

我有两个查询，每个查询将输出2列。他们来自同一张桌子。

查询1

SELECT MONTH(DateOrdered) AS MONTH,SUM(Downpayment)AS total FROM transaction WHERE YEAR(DateOrdered) = YEAR('2018-12-00') AND Status = 'Ongoing' GROUP BY MONTH(DateOrdered)


MONTH-----total

10------------4590

12------------1497.5

查询2

SELECT MONTH(DateFinish) AS MONTH,SUM(Total-Downpayment)AS total FROM transaction WHERE YEAR(DateFinish) = YEAR('2018-12-00') AND Status = 'Complete' GROUP BY MONTH(DateFinish)


MONTH--------total

5-----------------1147.5

10----------------1647

12----------------1147.5

我想将两者和SUM结合起来，将2列称为total

例如

MONTH------------total

5--------------------1147.5

10--------------------6237

12--------------------2645

我现在有什么

SELECT MONTH(DateOrdered) AS MONTH,SUM(Downpayment) FROM transaction WHERE YEAR(DateOrdered) = YEAR('2018-12-00') AND Status = 'Ongoing' GROUP BY MONTH(DateOrdered) UNION SELECT MONTH(DateFinish) AS MONTH,SUM(Total-Downpayment) FROM transaction WHERE YEAR(DateFinish) = YEAR('2018-12-00') AND Status = 'Complete' GROUP BY MONTH(DateFinish)

显示

MONTH--------total

10----------------4590

12----------------1497.5

5-----------------1147.5

10----------------1647

12----------------1147.5

Answer 1

此处使用的高级概念是：1）联合查询和2）子查询

类似于以下内容：

Select 
    sum(total) as totalByMonth,
    month
from
(
    SELECT 
        MONTH(DateOrdered) AS MONTH,
        SUM(Downpayment)AS total 
    FROM 
        transaction 
    WHERE 
        YEAR(DateOrdered) = YEAR('2018-12-00') 
        AND Status = 'Ongoing' 
    GROUP BY 
        MONTH(DateOrdered)

    Union

    SELECT 
        MONTH(DateFinish) AS MONTH,
        SUM(Total-Downpayment)AS total 
    FROM 
        transaction 
    WHERE 
        YEAR(DateFinish) = YEAR('2018-12-00') 
        AND Status = 'Complete' 
    GROUP BY 
        MONTH(DateFinish)

) subQuery1

group by
    month

我需要合并2个查询，但需要对其中一部分进行汇总

1 个答案: