ST_PointN method for type ST

Returns the nth point in the linestring.

By default, ST_PointN uses the original format for a geometry, if it is available. Otherwise, the internal format is used. For more information about internal and original formats, see STORAGE FORMAT clause, CREATE SPATIAL REFERENCE SYSTEM statement.

linestring-expression.ST_PointN(n)

Name	Type	Description
n	INT	The position of the element to return, from 1 to linestring-expression.ST_NumPoints().

ST_Point If the linestring value is the empty set, returns NULL. If the specified position n is less than 1 or greater than the number of points, raises a warning and returns NULL. Otherwise, returns the ST_Point value at position n.
The spatial reference system identifier of the result is the same as the spatial reference system of the linestring-expression.

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