On Apr 5, 10:03 pm, "Ana C. Dent" <anaced..._at_hotmail.com> wrote:
> "John" <acide.ascorbi..._at_gmail.com> wrote in news:1175802637.291526.37550
> @p77g2000hsh.googlegroups.com:
>
>
>
> >> Is this the real problem or a simplification?
> > It's a simplification but not that much. The real problem involves
> > user_ids but this part can be skipped here.
>
> >> Is this something that will be run once or repeatedly?
> > Only once.
>
> >> Is it possible for the same time to be in A and B?
> > No, A and B are completely different data.
>
> >> Is it possible to have a B before an A beginning the sequence?
> >> Is it possible for there to be multiple Bs between As?
> > Yes everything is possible, A events and B events happen
> > independently.
>
> > Thanks for being interested in my problem!
>
> > John
>
> I would NOT use SQL to solve this problem.
> I'd use Perl or PL/SQL.
> Treat Table_A & Table_B as ordered lists (based upon field of choice;
> timestamp, ID , whatever).
> You only needs to pass thru each list a single time.
> Open two read loops; one on A & one on B.
> Read 1 record from each list.
> 1) If A < B, then read record from A.
> 2) If A < B, then you found 1st hit & read record from A
> 3) If B < A, then read record from B
> 4) If B < A, the you have a hit & read record from B
> etc. loop until no more records
Classic sort/merge logic. Something every cobol programmer learned
the first week on the job. Something we often forget with all of our
point/click/object programming. Sometimes the old, simple solutions
are still the best.
Received on Fri Apr 06 2007 - 09:44:29 CDT
