First of all, don't try to test everything at once - it's slow and it doesn't tell you which part is wrong.
For example, check if your query returns the right data. If not, there is no point in using it an RDP class and running the report.
If the query looks fine, your next step is debugging the RDP class and checking whether it inserts the right data to temporary tables.
Testing the report design would be the last step, but you already know that your problem is with the data preparation, therefore it's not really relevant in your case.
Back to your query. Unfortunately, you haven't told us much about it. First of all, are you using outer joins for HcmWorker data sources? If not, it's a problem, because then your query returns just orders with both WorkerPurchPlacer and Requester filled in, which likely isn't what you want.
