DB2 9 & 10 for z/OS Overview

Migration Planning WorkshopOLAP Built-in Functions• RANK– Generates a row number defining the rank as 1 plus the number of rowsthat precede the row.– If two or more rows are not distinct with respect to the ordering, there willbe one or more gaps in the sequential rank numbering. Also referred to asOlympic Ranking.• DENSE_RANK– Similar to RANK but ensures there are no gaps.• ROW_NUMBER– Creates a sequential row number that is computed for each row startingwith 1.– No number skipping.• Even though these functions are ordered, cursors remain updatable.32© 2011 IBM Corporation