HP Storage Essentials Storage Resource Management Report Optimizer Software 6.0 Building Reports Using the Web Intelligence Java Report Panel (August 2008)

Filtering data using subqueries and database ranking110
• Pre-ranking data reduces the amount of data retrieved across the network and stored in
Web Intelligence.
Note: You can perform a database ranking only if your database supports it. If this is not
the case, the Add a database ranking button is disabled on the Query Panel toolbar.
Databases that support ranking are Oracle, DB2, Terradata and Redbrick.
What can you do with a database ranking?
Database rankings allow you to answer questions like “Return the top 3 customers based
on the revenue they generated for each year” at the query level, without the need to return
data that falls outside the ranking to Web Intelligence and then filter it using a Web
Intelligence ranking.
How does a database ranking work?
A database ranking works by modifying the SQL that Web Intelligence generates to
retrieve the query data. If your database supports ranking, Web Intelligence generates
SQL to rank the data.
Note: Web Intelligence uses the SQL-99 Rank function in ranking SQL.
For more information on viewing the SQL generated by Web Intelligence, see ”Viewing
and editing the SQL behind the query definition” on page 43.)
Note: SQL is the query language supported by all relational databases (RDBMS), although
each database has its own syntax.
Ranking parameters
A ranking appears as follows in the Query Filters pane of the Query Panel:
The following table describes the parameters from left to right in the ranking:
Parameter Description
Top/Bottom Ranking order.
Top - ranks in descending order.
Bottom - ranks in ascending order.