ST_NumLineStrings function

The ST_NumLineStrings function takes a multilinestring as an input parameter and returns the number of linestrings that it contains.

If the given multilinestring is null or is empty, then null is returned.

This function can also be called as a method.

Syntax

Parameter

multilinestring: A value of type ST_MultiLineString that represents the multilinestring for which the number of linestrings is returned.

Return type

INTEGER

Example

Multilinestrings are stored in the SAMPLE_MLINES table. The ST_NumLineStrings function determines how many individual geometries are within each multilinestring.


SET CURRENT FUNCTION PATH = CURRENT FUNCTION PATH, db2gse
CREATE TABLE sample_mlines (id INTEGER, geometry ST_MultiLineString)

INSERT INTO sample_mlines
  VALUES (110, ST_MultiLineString ('multilinestring 
       ( (33 2, 34 3, 35 6),
         (28 4, 29 5, 31 8, 43 12),
         (39 3, 37 4, 36 7))', 1) )
INSERT INTO sample_mlines
  VALUES (111, ST_MultiLineString ('multilinestring 
       ( (3 2, 4 3, 5 6),
         (8 4, 9 5, 3 8, 4 12))', 1) )

SELECT id, ST_NumLineStrings (geometry) NUM_WITHIN
  FROM sample_mlines

Results:


ID          NUM_WITHIN
----------- ----------
        110          3
        111          2