Question

我需要运行一个select语句，它返回列值不相同的所有行（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

我阅读了很多帖子并尝试了不同的查询无济于事。我认为应该工作的查询如下。有人可以建议替代方案或告诉我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

这明显快于EXISTS方式：

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

Answer 2

您的查询不正确的是您通过电子邮件和名称进行分组，这组合了每组唯一的电子邮件和名称组合在一起，因此

aaron and aaron@gmail.com
christy and aaron@gmail.com
john and aaron@gmail.com

被视为3个不同的组，而不是所有属于1个单组。

请使用下面给出的查询：

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条件中使用子查询，这将增加记录在巨大的查询时间。

我建议使用Inner Join作为此问题的更好选择。

考虑相同的表，这可以给出结果

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

为了获得更好的效果，我建议您使用CustomerID或您桌子的任何唯一字段。可以复制CustomerName。

Answer 7

查询示例：

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

Answer 8

SELECT        Title, Id
FROM            dbo.TblNews
WHERE        (Title IN
      (SELECT  Title 
FROM dbo.TblNews AS TblNews_1
GROUP BY Title
HAVING (COUNT(*) > 1)))
ORDER BY Title

按标题排序

Answer 9

我正在寻找一个类似的查询，但是我正在寻找客户有多个价值的地方，但是要向多个活跃账户收费。例如：

Customer  Account  active
-------   -------  ------
john      123        y
john      123        y
john      456        y
mary      123        y
mary      123        y
alice     123        n
alice     456        y

所以我希望结果只返回john，因为john是唯一拥有多个处于活动状态的帐户的人。救命！另外，在实际提取数据之前，我想获得记录数。

Answer 10

找到非不同的行有一点点变化..

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

如何选择列值不明显的每一行

10 个答案: