SQL Spatial Join

sql join spatial

ss_norwalk · Oct 5, 2011 · Viewed 15.1k times · Source

I have 2 tables one with points as geographies and other with polygons as geographies. I am able to find which polygon a single point falls(from the point table) by the following query:

DECLARE @p geography;
select @p = PointGeom from dbo.PointTable where ID = 1 
SELECT  a.ID, ATTRIBUTE1, geom 
from dbo.PolygonTable  a
where geom.STIntersects(@p) = 1;

However, I want to do a join between the two tables and get the polygons in which each of the points in the Point Table fall. Is it even possible? Or do I need to loop through the Point table and call the above query multiple times?

Answer

This should work:

SELECT 
    polyTable.[PolygonID]
,   pointTable.[PointID]
FROM 
[PolygonTable_Name] polyTable WITH(INDEX([SPATIAL_INDEX_NAME]))
INNER JOIN 
[PointTabl_Name] pointTable
ON
polyTable.Geog.STIntersects(pointTable.Geog) = 1

I have added an index hint " WITH(INDEX(...)) " as this will speed up the query.

SQL Spatial Join

Answer

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