Hi, I have a spatial query with multiple OR statements, for large tables it's very slow. Is it possible to skip the spatial lookup on the other conditions if first(previous) condition equal 1, and thereby increase the performance?
SELECT vciia_main.sitrp,vciia_main.date_time from vciia_main, south_vietnam72, roads, rails, houses, city where st_within(vciia_main.geom, south_vietnam72.geom) and date_time is not null and (st_dwithin(vciia_main.geom, roads.geom, 500) OR st_dwithin(vciia_main.geom, rails.geom, 500) or st_dwithin(vciia_main.geom, city.geom, 800) or st_dwithin(vciia_main.geom, houses.the_geom, 500))
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Håvard Wahl Kongsgård
Peace Research Institute Oslo (PRIO)
http://havard.security-review.net/