Hive query generating identifiers for a sequence of row matching a condition

Question

Let\'s say I have the following hive table as input, let\'s call it connections:

userid  | timestamp   
--------|-------------
1       | 1433258019          


        

Answer 1

Interesting question. Per your comment to @Madhu, I added the line 2 1433258172 to your example. What you need is to increment every time timediff > 60 is satisfied. The easiest way to do this is to flag it and then cumulatively sum over the window.

Query:

select userid
  , timestamp
  , concat('user', userid, '-session-', s_sum) sessionid
from (
  select *
    , sum( counter ) over (partition by userid
                           order by timestamp asc
                           rows between unbounded preceding and current row) s_sum
  from (
    select *
      , case when timediff > 60 then 1 else 0 end as counter
    from (
      select userid
        , timestamp
        , timestamp - lag(timestamp, 1, 0) over (partition by userid
                                                 order by timestamp asc) timediff
      from connections ) x ) y ) z

Output:

1   1433258019  user1-session-1
1   1433258020  user1-session-1
2   1433258080  user2-session-1
2   1433258083  user2-session-1
2   1433258088  user2-session-1
2   1433258170  user2-session-2
2   1433258172  user2-session-2