An inexpensive test if a geometry might be within another.
      Syntax
         
            geometry-expression.ST_WithinFilter(
                  ST_Geometry
                geo2)
      
      Parameters
         
            - 
               geo2 – 
               The other geometry value that is to be compared to the geometry-expression.
            
Returns
         BIT Returns 1 if the geometry-expression might be within geo2, otherwise 0.
      Standards
         
            SQL/MM (ISO/IEC 13249-3: 2006) Vendor extension