Result value of one query used in predicate of another

[#1]

Is there a way to use the returned values from one query in the predicate of another.  The table with the data I require for my predicate comes from one database, and the table I wish to select utilizing that data exists in another.  To be more specific, I want to pull a date range from the first table and use those dates as my filter for the second table. 

I am new to Qlikview with no formal training, so apologize if this is an elementary problem. 

[#2]

Seems from my reading of other related posts, I might be able to pull this off by setting up a loop in my script.  For each iteration of the loop I would need to pull my begin and end dates from the first table, feed them into predicate of second query.  Note: second query is only returning agrigated data for the geven date range -- so one row each iteration.  Each iteration would add a new row so thinking I would need an identification column such as iteration number populated by a counter.  Desired end result would be table of aggrigated data per timeframe.  Does this sound like a valid methodology or am I going down the wrong path here?