Can I do it?

Just getting my feet wet with PHP and MYSQL, so I apologize if this seems like a simple question.

I need to add a parameter to a search function.

Currently I have

AND (this_field >= ? OR second_field >= ?)

I would like to add a field like so

AND (this_field >= ? OR second_field >= ? OR third_field >= ?)

Will that work? Any advise is appreciated.

So long as you also bind the third parameter or include it in the array when calling execute() you should be fine.

I am not sure what you mean by bind, but currently it is all wrapped up in a class. I then call the value if that makes sense?

Yes, that makes some sense, the reason I referred to bind was due to the ? placeholders shown in your query.

Here are a few of the possibilities on when those are used (they provide examples of what I was referring to)
http://www.php.net/manual/en/pdostatement.bindvalue.php
http://www.php.net/manual/en/pdostatement.bindparam.php
http://www.php.net/manual/en/pdostatement.execute.php

Thank you