If you've written a simple query that returns the values you want to see in the prompt, you can copy that SQL from the Advanced tab, and put it into your prompt.
I usually delete the "s_0"- type references(highlighted), and in the example below, I'd place my "Contracts"."Fund Source Code" into the ORDER BY statement.
As a shortcut you might want to try using OBIEE to generate the sql.
i.e. If you can create the analysis in answers that gives exactly what you want for the prompt then you can then set your diagnostics high, view the log file, get the physical sql and just copy that into the prompt area.