Re: Sessions at Trieste

Hi Pat and colleagues!

On Wed, 2008-05-14 at 11:37 -0700, Patrick Dowler wrote:
> Recognizing that this is a spatial join of s1 (all observed objects)
> with s2 (the observed objects with the specified properties), the
> intent can be expressed as:
>
> select
> s1.csys, s1.obsra, s1.obsdec, s1.z, s1.specid, s1.targetname,
> s1.quality
> from
> spectra as s1 JOIN spectra as s2 ON INTERSECTS(
> POINT(s1.csys, s1.obsra, s1.obsdec)
> CIRCLE(s2.csys,s2.obsra, s2.obsdec, 0.001) ) = 1
> where
> s2.quality > 3 and s2.redshift > 1.6
>

I think this is an elegant solution. There were some minor typos, so if it is used, this is syntactically correct (it went through the parser):

• Find all observed objects within 0.001 degrees of objects which
• have a redshift greater than 1.6 and a quality greater than 3. select s1.csys, s1.obsra, s1.obsdec, s1.z, s1.specid, s1.targetname, s1.quality from spectra as s1 INNER JOIN spectra as s2 ON INTERSECTS( POINT(s1.csys, s1.obsra, s1.obsdec), CIRCLE(s2.csys,s2.obsra, s2.obsdec, 0.001) ) = 1 where s2.quality > 3 and s2.redshift > 1.6 ;

Regards
Jeff

-- 
Jeff Lusted               tel: +44 (0)116 252 3581
Astrogrid Project         mob: +44 (0)7973 492290
Dept Physics & Astronomy  email: jl99-at-star.le.ac.uk
University of Leicester   web: http://www.astrogrid.org