  Long-established ranking approaches, such as top-k and skyline queries, have
been thoroughly discussed and their drawbacks are well acknowledged. New
techniques have been developed in recent years that try to combine traditional
ones to overcome their limitations. In this paper we focus our attention on
some of them: flexible skylines, regret minimization and skyline ranking
queries, because, while these new methods are promising and have shown
interesting results, a comparison between them is still not available. After a
short introduction of each approach, we discuss analogies and differences
between them with the advantages and disadvantages of every technique debated.
