PostGIS
Name
= — Returns `+TRUE+` if the coordinates and coordinate order geometry/geography A are the same as the coordinates and coordinate order of geometry/geography B.
Synopsis
boolean +`*`=`*`(` geometry `+A , geometry B );
boolean +`*`=`*`(` geography `+A , geography B );
Description
The = operator returns TRUE if the coordinates and coordinate
order geometry/geography A are the same as the coordinates and
coordinate order of geometry/geography B. PostgreSQL uses the =, <, and
> operators defined for geometries to perform internal orderings and
comparison of geometries (ie. in a GROUP BY or ORDER BY clause).
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Changed: 2.4.0, in prior versions this was bounding box equality not a geometric equality. If you need bounding box equality, use ~= instead.
This
method supports Circular Strings and Curves.
This
function supports Polyhedral surfaces.
Examples
SELECT 'LINESTRING(0 0, 0 1, 1 0)'::geometry = 'LINESTRING(1 1, 0 0)'::geometry;
?column?
----------
f
(1 row)
SELECT ST_AsText(column1)
FROM ( VALUES
('LINESTRING(0 0, 1 1)'::geometry),
('LINESTRING(1 1, 0 0)'::geometry)) AS foo;
st_astext
---------------------
LINESTRING(0 0,1 1)
LINESTRING(1 1,0 0)
(2 rows)
-- Note: the GROUP BY uses the "=" to compare for geometry equivalency.
SELECT ST_AsText(column1)
FROM ( VALUES
('LINESTRING(0 0, 1 1)'::geometry),
('LINESTRING(1 1, 0 0)'::geometry)) AS foo
GROUP BY column1;
st_astext
---------------------
LINESTRING(0 0,1 1)
LINESTRING(1 1,0 0)
(2 rows)
-- In versions prior to 2.0, this used to return true --
SELECT ST_GeomFromText('POINT(1707296.37 4820536.77)') =
ST_GeomFromText('POINT(1707296.27 4820536.87)') As pt_intersect;
--pt_intersect --
f