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).

	Only geometry/geography that are exactly equal in all respects, with the same coordinates, in the same order, are considered equal by this operator. For "spatial equality", that ignores things like coordinate order, and can detect features that cover the same spatial area with different representations, use ST_OrderingEquals or ST_Equals

	This operand will NOT make use of any indexes that may be available on the geometries. For an index assisted exact equality test, combine = with &&.

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)

Figure

SELECT 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)

01020000000200000000000000000000000000000000000000000000000000F03F000000000000F03F
010200000002000000000000000000F03F000000000000F03F00000000000000000000000000000000

Figure

Note: the GROUP BY uses the "=" to compare for geometry equivalency.

SELECT 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)

01020000000200000000000000000000000000000000000000000000000000F03F000000000000F03F
010200000002000000000000000000F03F000000000000F03F00000000000000000000000000000000

Figure

In versions prior to 2.0, this used to return true.

SELECT 'POINT(1707296.37 4820536.77)'::geometry =
   'POINT(1707296.27 4820536.87)'::geometry As pt_intersect;

 pt_intersect
--------------
 f
(1 row)

See Also

ST_Equals, ST_OrderingEquals, ~=