Groups and Calculated Items

You can create a group or calculated item as a way to display data in a table, pivot table, trellis, or graph. Groups and calculated items allow you to add new "members" to a column, when those members do not exist in the data source. These members are also known as "custom members."

A group is a static list of members that you select or a static or dynamic list that is generated by selection steps. A group is represented as a member. You can drill in a group that was created for a hierarchical column but not in one that was created for an attribute column.

A group uses the existing aggregation function of the measure column with which it is displayed. The aggregation is performed up from the lowest detail level in the Oracle BI Server, but no values are double-counted.
A calculated item is a computation between members, which is represented as a single member that cannot be drilled. When you create a calculated item, you add a new member in which you have selected how to aggregate the item, such as Sum or Average or a custom formula. The calculation is performed at the aggregated level, not at the lowest detail level.

Both groups and calculated items become selection steps for the analysis. Therefore, they apply to all views for that analysis. Both groups and calculated items can be saved as inline or named objects. For information, see "Inline or Named Objects".

What are Groups?

A group (also known as a "saved selection" in other products) is a user-defined member of a column. A group can be a list of members or a set of selection steps that can be executed to generate a list of members. All the members must be from the same attribute column or hierarchical column, and in a hierarchical column, members can be from different hierarchy levels. Groups are always displayed at the bottom of the column list in the order in which they were added (as shown in the Selection Steps pane). Groups can contain members or other groups.

You can save a group to the catalog and reuse it. For example, you can apply a group to analysis and dashboard column prompts or variable prompts. If a group is applied to a prompt, then the prompt presents either the group as a choice list option or members of the group as choice list options to the user at runtime.

What are Calculated Items?

A calculated item is a calculation between members, which is represented as a single member. A calculated item enables you to override the default aggregation rule that is specified in the Oracle BI repository, and for an existing analysis, the aggregation rule chosen by the designer. You can define a calculated item using a custom formula (which is the default) or by combining selected members with a function (for example, SUM).

A calculated item is a user-defined member of a column. A calculated item can contain members or other calculated items. Calculated items are always displayed at the bottom of the column list in the order in which they were added (as shown in the Selection Steps pane). You can save a calculated item to the catalog and reuse it.

A calculated item is useful when you want to view and manipulate a set of members as a single entity. For example, you might define calculated items for the following:

Key accounts in a geographic region
High-end products
Non-standard time periods, such as the first three weeks in September

You can create calculated items for columns in various places. Calculations differ from the default aggregation rules that are applied to measures, as described in Adding Totals to Tables and Pivot Tables. Internally, calculated items are processed as SQL SELECT statements, and the indicated functions are performed on the result set. For more information about SQL functions, see Appendix D, "Logical SQL Reference."