Available in versions: Dev (3.20) | Latest (3.19) | 3.18 | 3.17 | 3.16

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. For example:

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

sdo_util.extract(geometry, 1, 1 + 1)

SQLServer

geometry.STInteriorRingN(1)

ASE, Access, BigQuery, DB2, Derby, DuckDB, Exasol, Firebird, H2, HSQLDB, Hana, Informix, MemSQL, SQLDataWarehouse, SQLite, Sybase, Teradata, Trino, Vertica, YugabyteDB

/* UNSUPPORTED */

(These are currently generated with jOOQ 3.20, see #10141), or translate your own on our website

Feedback

Do you have any feedback about this page? We'd love to hear it!

The jOOQ Logo