Newbie attack...

Hi. I'm Achilles from Greece and I have been into PHP for 3 or 4 weeks. So far I've read 2 books about it and a lot of the online manual. But now I've come onto a problem and I'm asking you for help. I've designed a site which is completely based onto PHP and mySQL. What I mean is that all the main links are actually records into a table with columns such as: id, title, contents etc. Every time a link is clicked the main page rebuilts itself using the id parameter of the link and by an SQL command finds the title and the text to show. So far so good. Everything is working great except the fact that when I put some php code into the 'text' field, in order to run en extra sql command in the page, it hangs and just prints the code as if it was just text. Propably because of some encoding that takes place by submitting the data from my form to the database. I've tried some urlencode() and htmlspec... combination but didn't actually make it... I hope that some of you are clever enough to understand what I'm saying (with my poor english) and kind enough to help me... Looking forward to hearing from you...