【SQL】Access里两表连接，where条件怎么写？

Question

请问一下

```想把第二张表连到第一张表里，条件是第二张表的business parter这个字段值，在第一张表能找到。
SELECT * INTO [Total Combined matched 2021-2019]
FROM (Select distinct [business partner], [purchase channel], [Time - Calendar day],[maintable_receipt number],[category],[article],[article name],[unit price]
from [mathced transaction filter]
union
select distinct [business partner], [purchase channel], [Time - Calendar day],[receipt number],[category],[article],[article name],[unit price]
from [repeat transaction in2019-2020 filter] where [repeat transaction in2019-2020 filter].[business partner] = [mathced transaction filter].[business partner]
)

运行后提示输入参考值，随便输了个数字进去，跑出来的结果我查了下并不对。。。
![img](https://img-mid.csdnimg.cn/release/static/image/mid/ask/102841716846166.PNG "#left")

Answer 1

union是合并结果，不是连接查询。
join是连接查询，可以用left join

SELECT * INTO [Total Combined matched 2021-2019]
FROM (Select distinct [business partner], [purchase channel], [Time - Calendar day],[maintable_receipt number],[category],[article],[article name],[unit price]
from [mathced transaction filter]
left join
select distinct [business partner], [purchase channel], [Time - Calendar day],[receipt number],[category],[article],[article name],[unit price]
from [repeat transaction in2019-2020 filter] where [repeat transaction in2019-2020 filter].[business partner] = [mathced transaction filter].[business partner]
)