Question

I have a table in SQL Server to record the IP of all the members’ login of my website.

    ID   MEMBER      IP       
    ---------------------------------------
    1    member1     1.1.1.1
    2    member2     2.2.2.2
    3    member3     1.1.1.1
    4    member3     3.3.3.3
    5    member4     3.3.3.3

I want to figure out a way to search for associated member and their associated IP.

First example,

• member1 logged in from 1.1.1.1 before
• member3 logged in from 1.1.1.1 and 3.3.3.3 before
• member4 logged in from 3.3.3.3 before

So, For member1:

• Associated members: member1, member3, member4
• Associated IPs : 1.1.1.1, 3.3.3.3

For member2, associated member is member2 and associated IP is 2.2.2.2 .

This association system is to help manage fake players and the number of members is big ( ~100k ). So loading time is a big issue.

My question:

• Is there a SQL Query to generate the list of associated members and associated IPs?

=======Table to test======

CREATE TABLE [dbo].[tblAssociation](
    [ID] [int] NULL,
    [Member] [nvarchar](50) NULL,
    [IP] [nvarchar](50) NULL
) ON [PRIMARY]

GO

INSERT INTO [tblAssociation] VALUES(1,'member1','1.1.1.1')
INSERT INTO [tblAssociation] VALUES(2,'member2','2.2.2.2')
INSERT INTO [tblAssociation] VALUES(3,'member3','1.1.1.1')
INSERT INTO [tblAssociation] VALUES(4,'member3','3.3.3.3')
INSERT INTO [tblAssociation] VALUES(5,'member4','3.3.3.3')

======shankar’s suggestion====

SELECT T1.Member, T1.IP, T2.Member 
FROM   tblAssociation T1 
INNER JOIN tblAssociation T2 ON T1.IP = T2.IP
AND T1.Member = 'member1'

if you try, I can only get associated member = member1, member3.

member4 is not there, but he should be associated because member4 and member3 connected to 3.3.3.3 before

Answer 1

Building on the same statement as shankar_pratap, following CTE would get you all related members to a given member. The real difficulty here is in knowing when to stop the recursion. For the recursion to stop, both q.ID <> a.ID and q.OriginalID <> r.ID are required.

SQL Statement

;WITH q AS (
  SELECT  OriginalID = r.ID
          , r.ID
          , r.Member
          , r.IP
  FROM    tblAssociation a
          INNER JOIN tblAssociation r ON r.IP = a.IP
  WHERE   a.Member = 'member1'
  UNION ALL
  SELECT  q.OriginalID
          , r.ID
          , r.Member
          , r.IP
  FROM    tblAssociation a
          INNER JOIN tblAssociation r ON r.IP = a.IP
          INNER JOIN q ON q.Member = a.Member AND q.ID <> a.ID
  WHERE   q.OriginalID <> r.ID
)
SELECT  DISTINCT ID
        , Member
        , IP
FROM    q

Result

ID  Member  IP
1   member1 1.1.1.1
3   member3 1.1.1.1
4   member3 3.3.3.3
5   member4 3.3.3.3