Extract(Read) > Transform(Test&Apply) > Load(Learn) Blog

December 28, 2006

On TopN Analysis: Rownum – Row_Number – Rank

Filed under: Oracle Performance — H.Tonguç Yılmaz @ 7:16 am

Here is another reason why you might test before making a decision on which function to use by your previous experiences. In this scenerio there is large partitioned log table just having a primary jey on nlog_id column and we want to find the last N inserted rows.

Code Listing 20 : On TopN Analysis: Rownum – Row_Number – Rank

Testing Information : the scripts mentioned are tested on Oracle Database 10g Enterprise Edition Release 10.2.0.2.0

Refences Used : On Top-n and Pagination Queries By Tom Kyte, Oracle Magazine Article

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