ST_NumInteriorRings
Applies to ❌ Open Source Edition ✅ Express Edition ✅ Professional Edition ✅ Enterprise Edition
This function returns the number of interior rings of a polygon geometry. For example:
create.select(stNumInteriorRings(
stGeomFromText("""
POLYGON (
(-3 -3, 3 -3, 3 3, -3 3, -3 -3),
(-2 -2, 2 -2, 2 2, -2 2, -2 -2),
(-1 -1, 1 -1, 1 1, -1 1, -1 -1)
)
""")
)).fetch();
The result being, for example
+---------------------+ | ST_NumInteriorRings | +---------------------+ | 2 | +---------------------+
To access the Nth interior ring (1-based), use ST_InteriorRingN.
Dialect support
This example using jOOQ:
stNumInteriorRings(geometry)
Translates to the following dialect specific expressions:
Aurora MySQL, Aurora Postgres, CockroachDB, MySQL, Postgres, Redshift, Snowflake
st_numinteriorring(geometry)
MariaDB
st_numinteriorrings(geometry)
Oracle
(
SELECT (nullif(
count(*),
0
) - 1)
FROM table(sdo_util.extract_all(geometry))
)
SQLServer
geometry.STNumInteriorRing()
ASE, Access, BigQuery, ClickHouse, DB2, Derby, DuckDB, Exasol, Firebird, H2, HSQLDB, Hana, Informix, MemSQL, SQLDataWarehouse, SQLite, Sybase, Teradata, Trino, Vertica, YugabyteDB
/* UNSUPPORTED */
(Generated with jOOQ 3.20. Translate your own SQL on our website
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