Beginner Question - How to make a collection based on SQL query results

So I have an initial SQL query that creates a list of jobs.  I then have another query that finds a list of outstanding purchase orders for each job.  What I can't figure out is how to add each iteration (Each list of purchase orders for a specific job) to a collection so that at the end I can print out the entire list of jobs and corresponding purchase orders.  Right now I am doing a For Each purchase order, map values, then add to collection, but it is not working.  Please see my attachment for a screen shot of the process.

I want the results to look like this on the webform grid:

Job Number 1

Outstanding PO 1

Outstanding PO 2

Outstanding PO 3

Etc. 

Job Number 2

Outstanding PO 1

Outstanding PO 2

Outstanding PO 3

Etc.

Can someone point me to what I'm missing?

Thanks.