I recently worked with an insurance company on an interesting issue involving dates. They had a series of records that all had a start date but no end (or cancel) date. The end date of a record was implicitly recognized as the start date of the next highest record. This article will show you how.
Con las funciones de OLAP RANK y DENSE_RANK disponibles en programación SQL desde hace un tiempo, resulta bastante fácil preguntar por las «n» ocurrencias de valor más alto en un conjunto de datos ordenado. Lo que se conoce como «TOP n».
With the SQL OLAP RANK and DENSE_RANK functions being around for a while in SQL programming, it is quite easy to query for the TOP XX from data.
DB2 includes support for On-Line Analytical Processing (OLAP) built-in functions. The first three functions introduced may be used to rank and number rows in a result table. This article will explore these three functions which are available on both DB2 for z/OS and DB2 for LUW.
Here are some links from IDUG's big data primer article for quick reference