Returns the boundary length of an ST_Polygon, or the sum of the boundary lengths of the component polygons of an ST_MultiPolygon.
Returns a FLOAT value.
ST_Polygon or ST_MultiPolygon
Note: This method can be called on 3D geometries (those that include z coordinates). However, the z coordinate is ignored in method calculations.
WHERE cityShape.ST_Perimeter() < 5E1
ORDER BY cityName;