MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6
The functions listed in this section do not restrict their argument and accept a geometry value of any type.
            ST_Dimension() and
            Dimension() are synonyms. For
            more information, see the description of
            ST_Dimension().
          
            Dimension() is deprecated;
            expect it to be removed in a future MySQL release. Use
            ST_Dimension() instead.
          
            ST_Envelope() and
            Envelope() are synonyms. For
            more information, see the description of
            ST_Envelope().
          
            Envelope() is deprecated;
            expect it to be removed in a future MySQL release. Use
            ST_Envelope() instead.
          
            ST_GeometryType() and
            GeometryType() are synonyms.
            For more information, see the description of
            ST_GeometryType().
          
            GeometryType() is deprecated;
            expect it to be removed in a future MySQL release. Use
            ST_GeometryType() instead.
          
            ST_IsEmpty() and
            IsEmpty() are synonyms. For
            more information, see the description of
            ST_IsEmpty().
          
            IsEmpty() is deprecated;
            expect it to be removed in a future MySQL release. Use
            ST_IsEmpty() instead.
          
            ST_IsSimple() and
            IsSimple() are synonyms. For
            more information, see the description of
            ST_IsSimple().
          
            IsSimple() is deprecated;
            expect it to be removed in a future MySQL release. Use
            ST_IsSimple() instead.
          
            ST_SRID() and
            SRID() are synonyms. For more
            information, see the description of
            ST_SRID().
          
            SRID() is deprecated; expect
            it to be removed in a future MySQL release. Use
            ST_SRID() instead.
          
            Returns the inherent dimension of the geometry value
            g, or NULL if
            the argument is NULL. The dimension can
            be −1, 0, 1, or 2. The meaning of these values is
            given in Section 11.4.2.2, “Geometry Class”.
          
mysql> SELECT ST_Dimension(ST_GeomFromText('LineString(1 1,2 2)'));
+------------------------------------------------------+
| ST_Dimension(ST_GeomFromText('LineString(1 1,2 2)')) |
+------------------------------------------------------+
|                                                    1 |
+------------------------------------------------------+
            ST_Dimension() and
            Dimension() are synonyms.
          
            Returns the minimum bounding rectangle (MBR) for the
            geometry value g, or
            NULL if the argument is
            NULL. The result is returned as a
            Polygon value that is defined by the
            corner points of the bounding box:
          
POLYGON((MINX MINY, MAXX MINY, MAXX MAXY, MINX MAXY, MINX MINY))
mysql> SELECT ST_AsText(ST_Envelope(ST_GeomFromText('LineString(1 1,2 2)')));
+----------------------------------------------------------------+
| ST_AsText(ST_Envelope(ST_GeomFromText('LineString(1 1,2 2)'))) |
+----------------------------------------------------------------+
| POLYGON((1 1,2 1,2 2,1 2,1 1))                                 |
+----------------------------------------------------------------+
            If the argument is a point or a vertical or horizontal line
            segment, ST_Envelope()
            returns the point or the line segment as its MBR rather than
            returning an invalid polygon:
          
mysql> SELECT ST_AsText(ST_Envelope(ST_GeomFromText('LineString(1 1,1 2)')));
+----------------------------------------------------------------+
| ST_AsText(ST_Envelope(ST_GeomFromText('LineString(1 1,1 2)'))) |
+----------------------------------------------------------------+
| LINESTRING(1 1,1 2)                                            |
+----------------------------------------------------------------+
            ST_Envelope() and
            Envelope() are synonyms.
          
            Returns a binary string indicating the name of the geometry
            type of which the geometry instance
            g is a member, or
            NULL if the argument is
            NULL. The name corresponds to one of the
            instantiable Geometry subclasses.
          
mysql> SELECT ST_GeometryType(ST_GeomFromText('POINT(1 1)'));
+------------------------------------------------+
| ST_GeometryType(ST_GeomFromText('POINT(1 1)')) |
+------------------------------------------------+
| POINT                                          |
+------------------------------------------------+
            ST_GeometryType() and
            GeometryType() are synonyms.
          
            This function is a placeholder that returns 0 for any valid
            geometry value, 1 for any invalid geometry value, or
            NULL if the argument is
            NULL.
          
            MySQL does not support GIS EMPTY values
            such as POINT EMPTY.
          
            ST_IsEmpty() and
            IsEmpty() are synonyms.
          
            Returns 1 if the geometry value g
            has no anomalous geometric points, such as self-intersection
            or self-tangency.
            ST_IsSimple() returns 0 if
            the argument is not simple, and NULL if
            the argument is NULL.
          
The descriptions of the instantiable geometric classes given under Section 11.4.2, “The OpenGIS Geometry Model” includes the specific conditions that cause class instances to be classified as not simple.
            ST_IsSimple() and
            IsSimple() are synonyms.
          
            Returns an integer indicating the spatial reference system
            ID associated with the geometry value
            g, or NULL if
            the argument is NULL.
          
mysql> SELECT ST_SRID(ST_GeomFromText('LineString(1 1,2 2)',101));
+-----------------------------------------------------+
| ST_SRID(ST_GeomFromText('LineString(1 1,2 2)',101)) |
+-----------------------------------------------------+
|                                                 101 |
+-----------------------------------------------------+