ST_NumInteriorRings()¶
TL;DR¶
Use ST_NumInteriorRings() to count a polygon’s interior rings.
Returns the number of interior rings in a polygon.
Syntax¶
ST_NumInteriorRings(geom)
ST_NumInteriorRing(geom)
Alias: ST_NumInteriorRing is a registered alias for ST_NumInteriorRings; it does not have a separate reference page.
Arguments¶
Argument |
Description |
|---|---|
|
A |
Return Value¶
Returns int64.
Usage Notes¶
Examples¶
DROP DATABASE IF EXISTS geo_accessor_demo;
CREATE DATABASE geo_accessor_demo;
USE geo_accessor_demo;
SELECT ST_NumInteriorRings(ST_GeomFromText('POLYGON((0 0,10 0,10 10,0 10,0 0),(2 2,4 2,4 4,2 4,2 2))')) AS interior_ring_count;
DROP DATABASE geo_accessor_demo;