The ST_MaxM function takes a geometry
as an input parameter and returns its maximum M coordinate.
If the given geometry is null or is empty, or if it does
not have M coordinates, then null is returned.
This function
can also be called as a method.


Parameter
- geometry
- A value of type ST_Geometry or one of its subtypes for which the
maximum M coordinate is returned.
Examples
- Example 1
This example illustrates the use of the ST_MaxM function. Three
polygons are created and inserted into the SAMPLE_POLYS table.
SET CURRENT FUNCTION PATH = CURRENT FUNCTION PATH, db2gse
CREATE TABLE sample_polys (id INTEGER, geometry ST_Polygon)
INSERT INTO sample_polys
VALUES (1, ST_Polygon('polygon zm ((110 120 20 3,
110 140 22 3,
120 130 26 4,
110 120 20 3))', 0) )
INSERT INTO sample_polys
VALUES (2, ST_Polygon('polygon zm ((0 0 40 7,
0 4 35 9,
5 4 32 12,
5 0 31 5,
0 0 40 7))', 0) )
INSERT INTO sample_polys
VALUES (3, ST_Polygon('polygon zm ((12 13 10 16,
8 4 10 12,
9 4 12 11,
12 13 10 16))', 0) )
- Example 2
This example finds the maximum M coordinate of each polygon
in SAMPLE_POLYS.
SELECT id, CAST ( ST_MaxM(geometry) AS INTEGER) MAX_M
FROM sample_polys
Results:
ID MAX_M
----------- ------------
1 4
2 12
3 16
- Example 3
This example finds the maximum M coordinate that exists for
all polygons in the GEOMETRY column.
SELECT CAST ( MAX ( ST_MaxM(geometry) ) AS INTEGER) OVERALL_MAX_M
FROM sample_polys
Results:
OVERALL_MAX_M
--------------
16