Wildcard in MySQL Query

I hope someone can help, as my issue is similar to Tom Denmark's.
I'm a novice and know very little about Dreamweaver, PHP or MySQL.

I want to display records based on the value from 2 drop-down boxes. Is there a way to set a 'wildcard-type' default value?
I've tried '-1' '%' and '_', with both text and numeric data ypes. I've even tried a clean install of Dreamweaver without the 8.0.2 update.

Some people have suggest what appear to be horrendous manual SQL statements, but I can't work out where to insert them into the code, and, to be honest, if I wanted to do that I wouldn't be using Dreamweaver in the first place!

Please, please, please can someone help as I've been looking for an understandable answer for a month now, without success.

PS - To see what I'm trying to do, go here