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st_geometryn function

Applies to: check marked yes Databricks SQL check marked yes Databricks Runtime 17.1 and above

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note

This feature is not available on Databricks SQL Classic warehouses. To learn more about Databricks SQL warehouses, see SQL warehouse types

Returns the 1-based n-th element of the input geometry as a GEOMETRY value.

Syntax​

st_geometryn ( geo, n )

Arguments​

  • geo: A GEOMETRY value.
  • n: The 1-based index of the element to retrieve.

Returns​

A value of type GEOMETRY, representing the n-th element of the input geometry.

If the input is a multipoint, a multilinestring, a multipolygon, or a geometry collection, the function returns the n-th element, or returns an error if the element does not exist.

If the input is a non-empty point, linestring, or polygon and the value of the index is equal to 1, the function returns the input as a GEOMETRY value, otherwise returns an error.

The SRID value of the output geometry is the same as that of the input value.

Note that indices smaller than 1 are not supported, and will result in an error.

The function returns NULL if the input is NULL.

Error conditions​

Examples​

SQL
-- Returns the second element of a geometry collection.
> SELECT st_astext(st_geometryn(st_geomfromtext('GEOMETRYCOLLECTION(POINT(4 5),LINESTRING(10 3,24 37,44 85))'), 2));
  LINESTRING(10 3,24 37,44 85)
-- Returns the first element of a multipoint.
> SELECT st_astext(st_geometryn(st_geomfromtext('MULTIPOINT((1 2),(3 4),(5 6))'), 1));
  POINT(1 2)
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