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* use of geometric types in select ?
@ 2003-02-27 21:07 dhoubrechts <dhoubrechts@cybernet.be>
0 siblings, 1 reply; 2+ messages in thread
From: dhoubrechts @ 2003-02-27 21:07 UTC (permalink / raw)
To: pgsql-sql
I create a db : createdb geo
I log into the db : psql geo
I create a table named poly :
geo=# create table poly (parc varchar(15), graphic polygon);
I populate the table :
insert into poly values('A52','(2,1),(1,3),(2,5),(4,6),(6,4),(5,2)');
insert into poly values('A135','(3,3),(7,4),(8,2),(4,1)');
Now I would look if the first polygon overlaps the second using the
varchars for retriving the poly.
I could do it so :
geo=# select '((2,1),(1,3),(2,5),(4,6),(6,4),(5,2))'::polygon &&
'((3,3),(7,4),(8,2),(4,1))'::polygon;
?column?
----------
t
(1 row)
Now, how can I do to have something like :
geo=# select graphic::polygon from poly where parc='A52' && select
graphic::polygon from poly where parc='A135';
Thanks for help
Didier.
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: use of geometric types in select ?
@ 2003-03-01 08:37 Victor Yegorov <viy@pirmabanka.lv>
parent: dhoubrechts <dhoubrechts@cybernet.be>
0 siblings, 0 replies; 2+ messages in thread
From: Victor Yegorov @ 2003-03-01 08:37 UTC (permalink / raw)
To: pgsql-sql
* dhoubrechts <dhoubrechts@cybernet.be> [01.03.2003 03:32]:
> I create a db : createdb geo
> I log into the db : psql geo
> I create a table named poly :
> geo=# create table poly (parc varchar(15), graphic polygon);
>
> I populate the table :
> insert into poly values('A52','(2,1),(1,3),(2,5),(4,6),(6,4),(5,2)');
> insert into poly values('A135','(3,3),(7,4),(8,2),(4,1)');
>
> Now I would look if the first polygon overlaps the second using the
> varchars for retriving the poly.
> I could do it so :
> geo=# select '((2,1),(1,3),(2,5),(4,6),(6,4),(5,2))'::polygon &&
> '((3,3),(7,4),(8,2),(4,1))'::polygon;
> ?column?
> ----------
> t
> (1 row)
> Now, how can I do to have something like :
> geo=# select graphic::polygon from poly where parc='A52' && select
> graphic::polygon from poly where parc='A135';
Something like this:
select (g1.graphic && g2.graphic) from poly g1, poly g2
where g1.parc = 'A52' and g2.parc = 'A135';
--
Victor Yegorov
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