Supporting ranking and clustering as generalized order-by and group-by
Chengkai Li, Min Wang, Lipyeow Lim, Haixun Wang, Kevin Chen–Chuan Chang · 2007
The Boolean semantics of SQL queries cannot adequately capture the "fuzzy" preferences and "soft" criteria required in non-traditional data retrieval applications. One way to solve this problem is to add a flavor of "information retrieval" into database queries by allowing fuzzy query conditions and flexibly supporting grouping and ranking of the query results within the DBMS engine. While ranking is already supported by all major commercial DBMSs natively, support of flexibly grouping is still very limited (i.e., group-by).