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Geography Methods Supported by Spatial Indexes

Under certain conditions, spatial indexes support the following set-oriented geography methods: STIntersects(),STEquals(), and STDistance(). To be supported by a spatial index, these methods must be used within the WHERE clause of a query, and they must occur within a predicate of the following general form:

geography1.method_name(geography2) comparison_operatorvalid_number

To return a non-null result, geography1 and geography2 must have the same Spatial Reference Identifier (SRID). Otherwise, the method returns NULL.

Spatial indexes support the following predicate forms:

  • geography1.STIntersects(geography2) = 1

  • geography1.STEquals(geography2) = 1

  • geography1.STDistance(geography2) < number

  • geography1.STDistance(geography2) <= number


    In either form of STDistance() predicate, at least one of geography arguments (geography1 or geography2) must specify a geography instance that represents a point. Otherwise, the method returns NULL.