OBIEE 11g features a new ability to create custom groupings of attribute column members, and there are two separate mechanisms that may be used: Groups and Calculated Items. What is the difference between them?
1.
Create
this new analysis from the Sample Sales subject area. The filter returns all values of P1 Product
that contain the letter 'p'.
2.
Modify
the Table view to add a row of grand totals.
Notice that the formula for 20 Actual Unit Price is correctly
recalculated on the grand total row at 8.926 per unit of quanitity sold.
Now
we'll create the first new object, a Custom Group called Group P.
3.
On
the Results tab, click the New Group icon on the toolbar.
4.
Use
the same logic as shown above to select the same 5 values of P1 Product and
click OK.
5.
Notice
that a new row labelled Group P has been added to the analysis, and the values
on that row are correct.
Now
let's create a Calculated Item
6.
Click
the New Calculated Item icon on the toolbar.
7.
Use
the same logic to make the same 5 values of P1 Product available in the left
window.
8.
One at a time, highlight a value in the left window, and shuttle
it to the right window using the 
icon.
After shuttling a value, follow it with a + sign (except for the last
one) so that the final formula looks like this:
icon.
After shuttling a value, follow it with a + sign (except for the last
one) so that the final formula looks like this:
9.
Click
OK to close the Calculated Item dialog.
10.
The
results now show a new row for Item P, but not all of its values are correct.
So
there we see the difference between Groups and Calculated Items. Custom Groups respect and reevaluate the
formulas for calculated columns such as Actual Unit Price. In other words, the aggregation methods for
the columns are retained. But Calculated
Items perform the exact calculation entered on the New Calculation Item screen,
no matter what fact column is involved.
In this case, if you add the 5 values of Actual Unit Price, the total is
45.952.
Which
begs the next question: Under what circumstances would you ever want to use a
Calculated Item instead of a Custom Group?
I'm not able to think of a reason.
Each
of these new objects may be saved for future use with other analyses.
11.
On
the Results tab, expand the Selection Steps panel at the bottom of the screen.
12.
Click
on the Group P link then select Save
Group As.
13.
Save
the group as Group P in the proper
subject area folder. Group P is now
available for reuse in the Selection Steps panel for any other analysis.
14.
The
same process applies for Item P as
well.
