Remove points from curves so long as the maximum introduced error is less than a specified tolerance.
      Syntax
         
            geometry-expression.ST_Simplify(DOUBLE tolerance)
      
      Parameters
         
            - 
               tolerance – 
               The maximum tolerance to use while simplifying.
            
Returns
         ST_Geometry Returns a simplified geometry with some points removed.
      Standards
         
            SQL/MM (ISO/IEC 13249-3: 2006) Vendor extension