Question

`我有2个表：收入和销售额，我想在查询中显示：

a）收入总和
b）销售总额
c）现在的产品数量 - a-b之间的差异

表'收入'有字段：Incomeid，ProductId，quant等表'sales'包含字段：SalesId，IncomeId，ProductId，quant等。

我的SQL是：

select i.productId, sum(i.quant) as iq, sum(s.quant) as sq    
from income i,sales s  
where (i.incomeId=s.incomeId)  
group by i.productId

或

select i.productId, sum(i.quant) as iq, sum(s.quant) as sq  
from income  
left outer join  s on  (i.IncomeId=s.IncomeId)  
group by i.productId

我的目标是如下结果：

现在的总和（收入）总和（销售额）

1 200 50 150
2 150 20 130
3 120 100 20

但我得错了（收入）：
Id sum（收入）总和（销售额）现在

1 20000 50 19950
2 27500 20 27480
3 125000 100 12400

如何编写SQL查询以获取此信息？

有关信息，我的数据库服务器是Interbase 2009。提前谢谢！

Answer 1

我会用：

select incomecode,
       sum(case when which = 'income' then sum_amt else 0 end) as sum_income,
       sum(case when which = 'sales' then sum_amt else 0 end) as sum_sales,
       sum(case when which = 'income' then sum_amt else 0 end)
     - sum(case when which = 'sales' then sum_amt else 0 end) as diff_between
  from (select incomecode, sum(quant) as sum_amt, 'income' as which
          from income
         group by incomecode
        union all
        select incomecode, sum(quant), 'sales'
          from sales
         group by incomecode) x
group by incomecode

Interbase似乎不支持内联视图，并且在您的版本中，还不支持case语句。在这种情况下，请尝试以下方法：

步骤1：创建收入总额视图

create view income_vw
select incomecode, sum(quant) as sum_amt
  from income
 group by incomecode

第2步：为销售总额创建视图

create view sales_vw
select incomecode, sum(quant) as sum_amt
  from sales
 group by incomecode

步骤3：运行最终选择查询，该查询将使用这两个视图

select coalesce(i.incomecode, s.incomecode) as incomecode,
       coalesce(i.sum_amt, 0) as sum_income,
       coalesce(s.sum_amt, 0) as sum_sales,
       coalesce(i.sum_amt, 0) - coalesce(s.sum_amt, 0) as diff_between
  from income_vw i
  full outer join sales_vw s
    on i.incomecode = s.incomecode

2个选择语句中的2个不同表的求和函数。怎么了？

1 个答案: