尝试使用WAMP使用PhP，MySQL调用外部文件

I'm sure there is a simple answer to this, but I have been fumbling with everything for almost a week now and surrender. I am trying to build a shopping cart app and every coding solution I build will work when I include the code on the same page, but when I try to use an external page to run the function it does not seem to return the data. I have tried various monitoring techniques to determine what it is happening.I'm sure there is a simple answer to this, but