SQL Based Set-Level Enabling Comparisons for Apathetical Groups
In data warehousing and OLAP applications, scalar-level predicates in SQL become highly inadequate which needs to support set-level comparison semantics, i.e., comparing a group of tuples with several values. The authors present here a comprehensive review of the state-of-the-art processing a group of tuples with multiple values and to optimize the queries. Currently, complex SQL queries composed by scalar-level operations are difficult to write as well as challenging for database engine to optimize, which results in costly evaluation. Mostly available query processing algorithm does not take the advantage of the small-result-set property and heavily on the tuple-scan-based approach, which incurs intensive disk accesses and computations.