Grouping events into intervals using hedgehog rolling style
- I have a challenging SQL problem for you, – yelled one of my coworkers one morning entering my office and dropping on his way a few pictures, SQL server system views map and a visitors chair. – Much more interesting than all your alerts and twitter conversations! ( “Well”, I thought to myself, “it might beat the alerts but not the twitter conversations” ) The problem presented by him is as follows: There is a table containing information about a device’s, like phones or tablets, history of connections to hotspots as shown below: The idea was to bind together the above mentioned events into groups. Each group, or we can call it - an interval, should represent the time that any device was connected to the specific access point. Each time the device has moved to the new access point, a new interval should start. If there were no events for the specific device longer than 30 min, the next event should start a new interval even if the new event was reported on the same access p...