Re: Chain/Thread Problem - Mailing list pgsql-sql

From J Sensel
Subject Re: Chain/Thread Problem
Date
Msg-id SYadnZo2kN4VilijXTWcrg@giganews.com
Whole thread Raw
In response to Chain/Thread Problem  (sammynash@uboot.com (Sammy))
List pgsql-sql
Sammy..

A quick and dirty approach is something like this:

id|threadid|emailid|referenceid|pathlevel
---------------------------------------
1|t101|e323|null|0
2|t101|e545|e323|1
3|t101|e822|e545|2
4|t101|e999|e323|1
etc..

Do the sorting when you insert the records.  Then they can be quickly &
easily retrieved.  Otherwise you're looking at a recursive query.  Not very
efficient.  This way is crude but allows the engine to optimize queries with
indexes.

HTH

Jim


"Sammy" <sammynash@uboot.com> wrote in message
news:6729af8d.0305160646.d9ab2d2@posting.google.com...
> Hi,
>
> I have a SQL problem for you all. What SQL qurey would I have to make
> on the following table to extract the chain (thread) of emails in a
> conversation.
>
>
>          id|emailid|referenceid
>          -----------------------
>           1|  e125 |   Null             (Start of chain)
>           2|  r1fe |   e125             (2nd letter in chain)
>           ...
>           ...
>           n|  e4ju |   r1fe             (3rd in chain)
>
> ie
> a sucessulf qurey would return rows 1,2 & n because they are all in
> the chain.
>
> Hope you can help me with my problem,




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