MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6
MySQL provides a set of useful nonstandard functions for creating geometry values. The functions described in this section are MySQL extensions to the OpenGIS specification.
      These functions produce geometry objects from either WKB values or
      geometry objects as arguments. If any argument is not a proper WKB
      or geometry representation of the proper object type, the return
      value is NULL.
    
      For example, you can insert the geometry return value from
      Point() directly into a
      POINT column:
    
INSERT INTO t1 (pt_col) VALUES(Point(1,2));
          GeometryCollection(
        g
          [, g] ...)
          Constructs a GeometryCollection value from
          the geometry arguments.
        
          GeometryCollection() returns
          all the proper geometries contained in the arguments even if a
          nonsupported geometry is present.
        
          GeometryCollection() with no
          arguments is permitted as a way to create an empty geometry.
        
          Constructs a LineString value from a number
          of Point or WKB Point
          arguments. If the number of arguments is less than two, the
          return value is NULL.
        
          MultiLineString(
        ls
          [, ls] ...)
          Constructs a MultiLineString value using
          LineString or WKB
          LineString arguments.
        
          Constructs a MultiPoint value using
          Point or WKB Point
          arguments.
        
          MultiPolygon(
        poly
          [, poly] ...)
          Constructs a MultiPolygon value from a set
          of Polygon or WKB
          Polygon arguments.
        
          Constructs a Point using its coordinates.
        
          Constructs a Polygon value from a number of
          LineString or WKB
          LineString arguments. If any argument does
          not represent a LinearRing (that is, not a
          closed and simple LineString), the return
          value is NULL.