Returns the geometry value that represents the point set symmetric difference of two geometries.
SELECT NEW ST_Polygon( 'Polygon( (-1 -0.25, 1 -0.25, 1 2.25, -1 2.25, -1 -0.25) )' ) AS A , NEW ST_CurvePolygon( 'CurvePolygon( CircularString( 0 1, 1 2, 2 1, 1 0, 0 1 ) )' ) AS B , A.ST_SymDifference( B ) AS C
The following picture shows the result of the symmetric difference as the shaded portion of the picture. The symmetric difference is a multisurface that includes two surfaces: one surface contains all of the points from the square that are not in the circle, and the other surface contains all of the points of the circle that are not in the square. Union of a square and a circle
SQL/MM (ISO/IEC 13249-3: 2006) 5.1.21