Calculate an SSRS Report parameter based on another

Question

I am looking to create an SSRS 2008 report which will have three report parameters. The first parameter will be a date that the user will enter a value in. The second parameter, which the user will also enter a value in, will be a field taking a number. Based on these two values, the third parameter, another date, should be calculated as the number of days (second parameter) before the date entered in the first parameter. The third parameter will be used to generate the report.

(The reason for the number of days parameter is to generate the report for a date a certain number of days before a known date. This second parameter will have a default, but could be changed as needed by the user to account for weekends, holidays, etc.)

Alternatively, the user could enter both of the dates, with the number parameter indicating the number of days between them. This could be used for verification that the user entered appropriate values for the parameters.

So, is it possible to calculate a report parameter based on other parameters like this. If so, how?

Answer 1

For the third parameter, you would use a formula like this for the Default Value:

=DateAdd(DateInterval.Day,-Parameters!SecondParameter.Value,Parameters!FirstParameter.Value)

Make sure you change the names of the first 2 parameters to whatever you named them. After the first two are entered, this third one will be populated. Also, make sure it is listed in order in the Report Data window. If it isn't already last in there, use the blue arrows at the top to move it down or you'll get an error.