Question

我有这样的设置：

Username | IP
Foo      | 1.2.3.4
Bar      | 1.2.3.4
Baz      | 1.2.3.6

说我想找到用户“Foo”的替代帐户。这样的事情应该回归：

Username | IP
Bar      | 1.2.3.4

我如何在一个SQL查询中执行此类操作？

Answer 1

自我加入应该做的伎俩

这将为您提供具有多个

的所有用户

Select * from 
Table t1
INNER JOIN Table t2
ON t1.ip = t2.ip
and t1.Username  <> t2.Username

您可以根据需要调整

e.g。

Where
 t1.UserName = 'Foo'

Answer 2

SELECT * FROM TableName
 LEFT JOIN TableName AS TableName2 
 ON TableName2.IP = TableName.IP AND TableName2.Username != TableName.Username
 WHERE TableName.Username = 'Foo'

查找备用帐户，SQL

2 个答案: