SQL prepared statement how to select via multiple possible menu selections?

Question

So I have 4 menu selections (product, location, courseType, and category), all of which can be null (programmed using JSF but that should be irrelevant to this question, as

Answer 1

I tend to build dynamic queries with helper methods like this:

StringBuilder query = new StringBuidler();
query.append("SELECT foo, bar FROM baz");
query.append(buildProductClause(product));
query.append(buildLocationClause(location));
query.append(buildCourseTypeClause(courseType));
// etc...

You could use a member field to build an array of arguments if you want to still use a prepared statement.