Question

我有一个包含以下字段的表

id
entCode
postCode
addressLine1
addressLine2
addressLine3
addressLine4
addressLine5

id和entCode都是唯一的整数

我想要做的是重复数据删除，当然我可以这样做

select postCode, addressLine1, addressLine2, addressLine3, addressLine4, addressLine5
from addresses
group by postCode, addressLine1, addressLine2, addressLine3, addressLine4

然而，我还想做的是返回该地址的第一个ID和entCode，但我无法理解它 - 它将是select top 1 id, entcode但要匹配postCode +所有5个地址字段我不确定是否需要进行连接或其他操作。

提前致谢！

Answer 1

不确定我是否做得对，但也许您只是在寻找min()？

select min(id), min(entCode), postCode, addressLine1, addressLine2, addressLine3, addressLine4, addressLine5
from addresses
group by postCode, addressLine1, addressLine2, addressLine3, addressLine4

Answer 2

在几乎所有数据库中，您都可以使用row_number()：

select a.*
from (select a.*,
             row_number() over (partition by postCode, addressLine1, addressLine2, addressLine3, addressLine4, addressLine5 order by id) as seqnum
      from addresses a
     ) a
where seqnum = 1;

在SQL中重复记录但保留ID

2 个答案: