Question

这是我的查询，但结果为false，其中数字行不同，也就是说每当tableA选择2行而tableB选择3结果为假

select sum(tableA.value)+sum(tableB.value1) ) 
from tableA,tableB 
where tableA.data between '2016-01-21' and '2016-03-09' 
and tableB.date2 between '2016-01-21' and '2016-03-09'

Answer 1

您需要在加入之前在子查询中执行求和。一个简单的规则：永远不要在from子句中使用逗号。

select coalesce(avalue, 0) + coalesce(bvalue, 0)
from (select sum(a.value) as avalue
      from tableA a
      where a.data between '2016-01-21' and '2016-03-09' 
     ) a cross join
     (select sum(b.value) as bvalue
      from tableB b
      where b.data between '2016-01-21' and '2016-03-09' 
     ) b;

Answer 2

好的。所以这就是我的理解。您试图从两个不同的表中总结两列，并获得总计列的总和。不是??如果我错了，请纠正我。如果是这样的话那么

一个简单的子查询可以来救你。

Select 
    (Select SUM(value) From tableA 
            where data between '2016-01-21' and '2016-03-09') +
    (Select SUM(value1) From tableB 
            where date2 between '2016-01-21' and '2016-03-09') FinalValue

如何在两个日期之间的不同表中SUM两列

2 个答案: