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Returns the Nth interior linestring ring of the polygon geometry. Returns NULL if the geometry is not a polygon or the given N is out of range ST_InteriorRingN

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Signatures

ST_InteriorRingN(geom: Geometry, n: Integer)

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Parameters

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geom
Geometry
required
The input geometry.
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n
Integer
required
The index or count value.

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Return type

The resulting geometry.

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Example

SELECT ST_InteriorRingN(ST_GeomFromText('POLYGON((0 0, 0 5, 5 5, 5 0, 0 0), (1 1, 2 1, 2 2, 1 2, 1 1), (1 3, 2 3, 2 4, 1 4, 1 3), (3 3, 4 3, 4 4, 3 4, 3 3))'), 0)

LINESTRING (1 1, 2 1, 2 2, 1 2, 1 1)