[Qgis-user] PostGIS Queries

[Richard McDonnell]

Need a little help, this may not be the forum, but I thought I would 
throw it out there!
I am looking to minimise the search area in this query

SELECT objectid
FROM
level_1_20151206 AS A, water_polygon AS Z
WHERE
(SELECT ST_Overlaps (A.the_geom, Z.geom));

What I want to do is use the extent of A's geometry to limit the search 
for overlaps with Z if that makes sense!?
These are both large National coverage datasets.
Any help suggestions welcomed!!

Regards,

Richard.



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