Sql/PHP question

I am creating a page that will generate a report. On the first page I have drop down menus that you can select what you want in the report. The table, department, and location. So in the query, I have this: $query = "select * from $database_table where department = $department and location = $location"; Now this works fine if in the department menu I select a department, and in the location menu I select a location, but I also want to be able to show all. For instance I want to create a report on all items for a single department in all locations. Is there such a thing as a wildcard within a where statement? location = * doesn't work of course, but what else could I use. I could have an if/else statement that if department is set to all, then run one query, and if location is set to all run another, etc. But that could get to be a real mess if I decide to all things later on. Anyone have any ideas on how to go about this? Mike