I have 9 drop-downs, and depending on user selection, the search is going to use those values to create a table. Since the drop-down values are dynamically generated (each is linked to another), there is no way to know how many of the values will be used in the final search. I want to know how is it possible to use N values in a search dependent on a user selecting N values.
You can set the default to * in the drop-down. In addition to the query to populate dropdown with dynamic values, you can add static values. A common use for static values is to add "*" and set that to be the default.