HP Intelligent Management Center Standard Software Platform - Manual (Page 189)

For instance, suppose that you're reporting off of an MS SQL Server 7
database, which supports Case Logic. You need to include an If-Then-Else
calculation in your report, and you need to summarize that calculation for
each group in the report. By performing the calculation with an SQL
Expression field of the following form, you use your database's ability to
process Case Logic:
CASE DatabaseTable. "DatabaseField "
WHEN 'SpecifiedValue' THEN Calculation1
ELSE Calculation2
END
If a record's DatabaseField value is equal to SpecifiedValue, then
Calculation1
is performed; for all other records, Calculation2 is
performed. By incorporating the SQL Expression field, you take advantage
of your database server's ability to process Case Logic. Your report's grouping
consequently takes place on the server, even when you summarize the SQL
Expression field elsewhere in the report.
Note:
The SQL syntax in this example is specific to MS SQL Server 7. You may
need to refer to your database documentation or consult with your
Administrator in order to determine the syntax appropriate to your database.
Inserting summary and running total fields where
possible
Where possible, avoid creating formulas with global variables to calculate
summaries or running totals.
Instead, create summaries by clicking the Insert menu and then selecting
the appropriate command (Subtotal, Grand Total, or Summary). Create
running total fields by opening the Field Explorer, right-clicking Running Total
Fields, and then selecting New from the shortcut menu.
For general details on summarizing data, see Sorting, Grouping, and Totaling
and Running Totals .
Crystal Reports 2008 SP3 User's Guide 189
8 Designing Optimized Web Reports
Improving grouping, sorting, and totaling