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Editorial Team
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Asked: 2026-06-17T20:53:21+00:00

I’ve been learning Hive over the past 2 months, but I’m having trouble figuring

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I’ve been learning Hive over the past 2 months, but I’m having trouble figuring out how to do certain sequence based queries. Take this example:

  • I have a huge log consisting of user actions
  • Every user action has a date field but obviously may not be scanned in that order due to multiple log files from different machines
  • Each log can log a variety of different events. For this example, I will denote these as letters: A, B, C, D…

The problem: How would I write a query which asks, “On average, how many times does event A happen before B occurs”?

I know how to group the users and only take users which have done A, and B and average the number of A which occurred, but limiting by the first occurrence of B seems like it would be difficult. I think I might actually be able to do this by stringing together 10 or so nasty looking queries, but I was wanting to know if there was an easier way to do it that I don’t know of.

Thanks!

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1 Answer

  1. Editorial Team

    This is not something easy to map to SQL, especially in Hive, taking into account that Hive do not support joins different from equi-joins.
    In the same time we can leave a lot of heavy lifting to Hive, while doing the small part by ourselves.
    Idea I would suggest is: let hive to group together all events for the specific user. We can create our own agregation UDF which will calculate min date for A and B and give output 0,1,2,3 – if only A happens, Only B Happens, A happens before B , B happens before A.
    From there the rest of calculations is again trivial to do in Hive.

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