Re: SQL QUESTION (ADVANCED ??)

jos_at_zeus.wnc.nedlloyd.nl (Jos Kerssens) writes:

>So far I got a number of answers to my question but,
>unfortunately, I still didn'y get the one I need.
 

>Thanks a lot for the effort anyway.
 

>Let me explain why the answers so far don't suffice.
 

>Suppose I have a case like this:
 

> table A table B table C
> acol acol ccol ccol
 

> A1 A1 - C1 C1
> A2 A2 - C1 C2
> A3 A2 - C2 C3
> A4 A3 - C2 C4
> A5 A3 - C3 C5
> A4 - C3
> A4 - C4
> A5 - C4
> A5 - C5
 

>My entry value is A1.
 

>L. Scott Johnson's select statement would only give me:
 

>A1
>A2
 

>Hank Robinson's first statement would give:
 

>A1
>A2
 

>His second statement would give:
 

>A1
>A2
 

>The statement of Larry Kramer would give:
 

>A1
>A2
 

>And I really need:
 

>A1
>A2
>A3
>A4
>A5
 

>since they're all connected through the values of ccol.
>The table has (apart from the values above) also values that are not connected
>at all to A1 (f.i. A99 - C99 without any other record having A99 or C99).
>That's why I call A1 to A5 a 'group'.
 

>Making more subselects or joins as in the above statements wouldn't help,
>since I don't know how many I need.
 

>So, I guess we're still searching for the answer...
 

>Regards,

>Jos.
 

>P.S. It's not a matter of efficiency, I just need the data...

Hi Jos,

I'm terribly sorry but I guess SQL is not powerfull enough to solve your problem, because it can not handle recursive queries. As you stated you can't say that there are only n items connected, which could be handled by a query with n subqueries, so you need something like an iteration or recursion, and SQL unfortunately doesn't offer that.

I fear this is not much help for you.

Bye

Oliver

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Oliver Kuhn                      email:
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