Using Value passed from one report to the other

Summary

I am trying to pass a value into a dataset where clause

Content

I have 2 reports. Rpt 1 & Rpt 2.  Rpt 1 shows "Count of Days" and "Count of REQIDs".  Rpt 2 shows all the fields from the table the couns came from.  When the user clicks on the "Count of Days" cell in Rep 1, I want to know how to use the passed value within the second dataset as a WHERE Claus Value. 

Rpt 2 (Select * from DB.DS where (Value count) = CellValueSelected.)

Version

18

Code Snippet

SELECT
    po_hdr_entered_dt,
    req_hdr_entered_dt,
    req_hdr_business_unit,
    req_hdr_req_id,
    po_hdr_po_id,
    po_line_distrib_line_nbr,
    po_line_distrib_sched_nbr,
    po_line_distrib_dst_line_numb    
FROM
    BD.fact_req_to_po_days
    where(req_hdr_entered_dt - po_hdr_entered_dt) = :1