Обсуждение: Is this the most efficent way to child nodes off a N-ary node database?

I have created this SQL statment, used to pull the child/leaf nodes off of a
N-ary node structure in PostgreSQL.

Is my premise all wrong?

Is this efficent as a SQL select?

Should this be done in my code (something I try to avoid for abstraction
reasons)?
"SELECT DISTINCT t1.node_id FROM node t1 WHERE NOT EXISTS (SELECT
t1.node_id FROM node t2 WHERE t1.node_id = t2.parent_id);"

Christian,

take a look at our contrib/tree module, available from
http://www.sai.msu.su/~megera/postgres/gist/
Oleg
On Thu, 14 Feb 2002, Christian Brink wrote:

> I have created this SQL statment, used to pull the child/leaf nodes off of a
> N-ary node structure in PostgreSQL.
>
> Is my premise all wrong?
>
> Is this efficent as a SQL select?
>
> Should this be done in my code (something I try to avoid for abstraction
> reasons)?
>
>  "SELECT DISTINCT t1.node_id FROM node t1 WHERE NOT EXISTS (SELECT
> t1.node_id FROM node t2 WHERE t1.node_id = t2.parent_id);"
>
>
>
>
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Regards,    Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83