ST_M
The ST_M function takes a point as an input parameter and return its M (measure) coordinate.
If the specified point is null or is empty, then null is returned.
Syntax
Parameters
- point
- A value of type ST_Point for which the M coordinate is returned or modified.
Return type
DOUBLE
Examples
Example 1
This example
illustrates the use of the ST_M function. Three points are created
and inserted into the SAMPLE_POINTS table. They are all in the spatial
reference system that has an ID of 1.
SET CURRENT PATH = CURRENT PATH, db2gse;
CREATE TABLE sample_points (id INTEGER, geometry ST_Point);
INSERT INTO sample_points
VALUES (1, ST_Point (2, 3, 32, 5, 1));
INSERT INTO sample_points
VALUES (2, ST_Point (4, 5, 20, 4, 1));
INSERT INTO sample_points
VALUES (3, ST_Point (3, 8, 23, 7, 1));
Example 2
This example finds the M
coordinate of the points in the SAMPLE_POINTS table.
SELECT id, ST_M (geometry) M_COORD
FROM sample_points;
ID M_COORD
----------- ------------------------
1 +5.00000000000000E+000
2 +4.00000000000000E+000
3 +7.00000000000000E+000