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st_numinteriorrings function

Applies to: check marked yes Databricks Runtime 17.3 and above

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Returns the number of interior rings of the input polygon.

Syntax​

st_numinteriorrings ( geoExpr )

Arguments​

  • geoExpr: A GEOGRAPHY or GEOMETRY value.

Returns​

An INTEGER that specifies the count of interior rings in the input polygon.

Notes​

The function returns NULL if the input is NULL.

Error conditions​

Examples​

SQL
-- Example taking an empty 2D polygon GEOMETRY.
> SELECT ST_NumInteriorRings(ST_GeomFromText('POLYGON EMPTY', 4326));
  0
-- Example taking a 3DZ polygon GEOGRAPHY with one non-empty ring.
> SELECT ST_NumInteriorRings(ST_GeogFromText('POLYGON Z ((0 0 6,1 0 6,1 1 8,0 1 6,0 0 6))'));
  0
-- Example taking a 4D polygon GEOMETRY with two rings.
> SELECT ST_NumInteriorRings(ST_GeomFromText('POLYGON ZM ((0 0 111 -11,10 0 222 -22,0 10 333 -33,0 0 444 -44),(1 1 555 -55,4 1 666 -66,1 4 777 -77,1 1 888 -88))', 4326));
  1
-- Example taking a 3DM polygon GEOGRAPHY with three rings.
> SELECT ST_NumInteriorRings(ST_GeogFromText('POLYGON M ((0 0 1,10 0 2,0 10 3,0 0 1),(1 1 2,2 1 3,1 2 4,1 1 2),(3 3 3,3 2 4,2 3 5,3 3 3))'));
  2
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