MS Access，从两个表中获取总值

Question

我正在尝试从表 "sales" 和 "payment" 中获取总值，其中两个表中的 customer_id 与从表单的组合框中选择的客户相匹配。

Table 1：销售额

customer_id item    item_value
1           Fan     0
3           AC      0
1           Iron

Table 2：付款

customer_id amount
1           0
2           0
1           
4           0

我不确定如何编写查询以获得以下结果：

查询结果

customer_id total_purchase_amount   total_paid_amount
1           250                     0

感谢您的帮助！提前致谢

Answer 1

您可以使用相关子查询：

select s.customer_id, sum(s.item_value) as total_purchase_amount,
       (select sum(p.amount) 
        from Payment p 
        where p.customer_id = s.customer_id
       ) as total_paid_amount
from Sales s
where s.customer_id = ? -- you can pass here customer_id
group by s.customer_id;

Answer 2

您可以加入两个求和表，例如：

select a.customer_id, a.total_purchase_amount, b.total_paid_amount
from
    (
        select s.customer_id, sum(s.item_value) as total_purchase_amount
        from sales s
        group by s.customer_id
    ) a left join
    (
        select p.customer_id, sum(p.amount) as total_paid_amount
        from payment p
        group by p.customer_id
    ) b on a.customer_id = b.customer_id

要按从您的组合框中选择的客户进行过滤，您可以包含一个 where 子句，例如：

where a.customer_id = Forms!YourForm!YourComboBox

您可能还想使用 Nz(b.total_paid_amount, 0) 为没有 Payment 记录的客户显示零。

MS Access，从两个表中获取总值

MS Access, getting total values from two tables

sql

ms-access

ms-access-2016