Prompt values from a table

[Rookie]

I am loading a run date value prompt from a table that has the associated from and to dates also on the table.  THe prompt page of my report allows the users to select a date range using a from and to Date prompt or they can select a run date at which point my report must use and display the from and to date associated with the run_date selected on the report output.  How do I obtain the from & to date from the table that is being used to load the run_date promt when run_date is selected?
Thanks in advance

[Gyana.Sahoo]

Use 'Caption' function in the main Query.

Caption( Date ) between ?from date? and ?to date?

[Gyana.Sahoo]

Plz try that & let me know