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

ST_ExteriorRing

Applies to ❌ Open Source Edition   ✅ Express Edition   ✅ Professional Edition   ✅ Enterprise Edition

This function returns a linestring corresponding to the exterior ring of a polygon geometry. For example:

create.select(stExteriorRing(
  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_ExteriorRing                            |
+--------------------------------------------+
| LINESTRING (-3 -3, 3 -3, 3 3, -3 3, -3 -3) |
+--------------------------------------------+

Or, visually:






Dialect support

This example using jOOQ:

stExteriorRing(geometry)

Translates to the following dialect specific expressions:

Aurora MySQL, Aurora Postgres, CockroachDB, MariaDB, MySQL, Postgres, Redshift, Snowflake

st_exteriorring(geometry)

Oracle

sdo_util.extract(geometry, 1, 1)

SQLServer

geometry.STExteriorRing()

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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