Count number of rows that are not within 10 seconds of each other

Question

I track web visitors. I store the IP address as well as the timestamp of the visit.

ip_address    time_stamp
180.2.79.3  1301654105
180.2.79.3  1301654106
180.2.         


        

Answer 1

Select Z.IP, Count(*) As VisitCount
From    (
        Select V.IP
        From visitors As V
            Left Join visitors As V2
                On V2.IP = V.IP
                    And V2.time_stamp > V.time_stamp
        Group By V.IP, V.time_stamp
        Having (Min(V2.time_stamp) - V.time_stamp) >= 10
        ) As Z
Group By Z.IP

This counts any visit where the next entry is more than 10 seconds away as a new visit.