According to one embodiment of the present invention, a level of a first hierarchy and a second hierarchy of data attributes is determined where the first hierarchy and the second hierarchy share the determined level and each subordinate hierarchical level. The embodiment further removes from a set of tuples of a database operation at least one tuple that lacks corresponding data in a data source based on the tuple containing elements corresponding to non-intersecting sets of attributes at the determined level. Embodiments of the present invention include a method, system and computer program product for reducing tuple sets in substantially the same manner described above.