EFFICIENT RANGE UNIONS IN SQL

In one embodiment, a union of the bounding boxes is computed of entities in a relational database indexed by a spatial index, filtered according to some criteria. For each of a set of targets to be considered, a bounding box of the target is tested against a current range union result. If the bounding box is completely contained in the current range union result, the target is excluded from further consideration. Otherwise, the target is processed. When the target is an entity, it is determined whether the entity meets the entity filtering criteria. If so a union is computed and the current range union result updated. When each of the targets to be considered in the spatial index has been subject to test or excluded, the current range union result is returned as a final range union result.