A parameter field does not have to be placed in a report in order to be used in a record or group selection formula. You create the parameter field and then enter it in your formula as you would any other field.
To decrease the amount of data transferred from the database server, and increase performance, incorporate parameter fields right into your record selection formula.
This record selection formula prompts users to enter a sales quota and displays all only those customers whose Last Year's Sales exceeded that sales quota.
{Customer.Last Year's Sales} > {?SalesQuota}
This Crystal syntax formula incorporates the parameter ?group, which prompts users to choose either Customer or Group as their group option. The UpperCase function converts the parameter value to uppercase for consistency.
WhileReadingRecords; If UpperCase ({?group})= "CUSTOMER" then {Customer.Customer Name} Else if UpperCase ({?group}) = "REGION" then {Customer.Region}
Parameter fields can be used to create conditional formatting formulas. You can use a conditional formatting formula to color-flag data that meets certain conditions. If the conditions under which you flag these items never change, you do not need to use parameter fields use formulas or conditional formatting.
This Crystal syntax formula incorporates the parameter ?SalesTarget, which prompts users for a sales target value. All customers who are over that sales target value will appear in red in the report.
If {Customer.Last Year's Sales} > {?SalesTarget} Then Red Else Black