如何select列值不相同的每一行

我需要运行一个select语句来返回列的值不是不同的所有行（例如EmailAddress）。

例如，如果表格如下所示：

CustomerName EmailAddress Aaron [e-mail] Christy [e-mail] Jason [e-mail] Eric [e-mail] John [e-mail] 

我需要查询返回：

 Aaron [e-mail] Christy [e-mail] John [e-mail] (peer edited from [e-mail]) 

我读了很多post，尝试了不同的查询无济于事。 我认为应该工作的查询如下。 有人可以提出一个替代scheme或告诉我什么可能是我的查询错？

 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) 

Answer 2

你的查询不正确的事情是，你是通过电子邮件和名称分组，形成一组每个独特的电子邮件和名称组合在一起，因此

 aaron and [e-mail] christy and [e-mail] john and [e-mail] 

被视为3个不同的组，而全部属于1个单独的组。

请使用下面的查询：

 select emailaddress,customername from customers where emailaddress in (select emailaddress from customers group by emailaddress having count(*) > 1) 

Answer 3

怎么样

 SELECT EmailAddress, CustomerName FROM Customers a WHERE Exists ( SELECT emailAddress FROM customers c WHERE a.customerName != c.customerName AND a.EmailAddress = c.EmailAddress) 

Answer 4

 select CustomerName,count(1) from Customers group by CustomerName having count(1) > 1 

Answer 5

只是为了好玩，这是另一种方式：

 ;with counts as ( select CustomerName, EmailAddress, count(*) over (partition by EmailAddress) as num from Customers ) select CustomerName, EmailAddress from counts where num > 1 

Answer 6

而不是在where条件下使用子查询，这将增加查询时间，其中logging是巨大的。

我build议使用Inner Join作为这个问题的更好的select。

考虑到同一个表，这可能会给出结果

 SELECT EmailAddress, CustomerName FROM Customers as a Inner Join Customers as b on a.CustomerName <> b.CustomerName and a.EmailAddress = b.EmailAddress 

为了更好的结果，我build议你使用CustomerID或你的表的任何独特的领域。 CustomerName名称的重复是可能的。

Answer 7

那么有一个轻微的变化，find不明显的行..

SELECT EmailAddress，CustomerName FROM Customers WHERE EmailAddress NOT IN（SELECT EmailAddress FROM Customers GROUP BY EmailAddress HAVING COUNT（*）> 1）