ST_InteriorRingN
Applies to ❌ Open Source Edition ✅ Express Edition ✅ Professional Edition ✅ Enterprise Edition
This function returns a linestring corresponding to the Nth interior ring (1-based) of a polygon geometry.
create.select(stInteriorRingN(
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)
)
""")
), 1).fetch();
The result being, for example
+--------------------------------------------+ | ST_InteriorRingN | +--------------------------------------------+ | LINESTRING (-2 -2, 2 -2, 2 2, -2 2, -2 -2) | +--------------------------------------------+
Or, visually:
To get the total number of interior rings, use ST_NumInteriorRings.
Dialect support
This example using jOOQ:
stInteriorRingN(geometry, 1)
Translates to the following dialect specific expressions:
Aurora MySQL, Aurora Postgres, CockroachDB, MariaDB, MySQL, Postgres, Redshift, Snowflake
st_interiorringn(geometry, 1)
Oracle
st_polygon(geometry).st_interiorringn(1)
SQLServer
geometry.STInteriorRingN(1)
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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