sql - 如何选择列值不不同的每一行

Question

我需要运行一个 select 语句，该语句返回列值不重复的所有行(例如 EmailAddress)。

例如，如果表格如下所示:

CustomerName     EmailAddress
Aaron            aaron@gmail.com
Christy          aaron@gmail.com
Jason            jason@gmail.com
Eric             eric@gmail.com
John             aaron@gmail.com

我需要返回查询:

Aaron            aaron@gmail.com
Christy          aaron@gmail.com
John             aaron@gmail.com

我读了很多帖子并尝试了不同的查询但无济于事。我认为应该有效的查询如下。有人可以提出替代方案或告诉我我的查询可能有什么问题吗？

select EmailAddress, CustomerName from Customers
group by EmailAddress, CustomerName
having COUNT(distinct(EmailAddress)) > 1

Answer 1

这比 EXISTS 方式快得多:

SELECT [EmailAddress], [CustomerName] FROM [Customers] WHERE [EmailAddress] IN
  (SELECT [EmailAddress] FROM [Customers] GROUP BY [EmailAddress] HAVING COUNT(*) > 1)