Re: FW: An SQL question , not easy ;-)

Give me some time :-)))
Jan Pruner

Dne st 15. srpen 2001 12:40 jste napsal(a):
> Dear gurus !
> I have a table of phone calls , 2 fields : CALL_START DATE ,
> CALL_END DATE .
> I need an SQL statement or a PL/SQL block to calculate the maximum
> number of SIMULTANIOUS phone conversations.
> Consider there are 4 calls ,
> one started at 12:10 and ended at 12:40
> second started at 12:15 and ended at 12:30
> third started at 12:25 and ended at 12:55.
> fourth started at 12:45 and ended at 12:47.
> So the first 3 calls are simultanious , for example they overlap at 12:28 ,
> i.e. there are 3 pairs of persons having phone conversation at 12:28.
> The third and fourth calls are simultanious at 12:46 ,i.e. there are 2
> pairs of persons having phone conversation at 12:46.
> So , i need the maximum number of concurrent phone conversations in my
> table.
> Thanks a lot !!!
>
> Please help !!!
> Thanks a lot in advance !
> Andrey.

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Author: Jan Pruner
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