PHP Back-End for SQL Query Form?

[evenmonkeys]

I'm not trying to make a page for the vBulletin admincp. It's for something entirely different.

PHP Code:

<?php
if($_POST[submit]){

AHHH WHAT GOES HERE!?!?!?

} else {
  echo("

<textarea name='sqlquery'></textarea>
<input type='submit' name='submit'>

  ");
}
?>

I have no idea what to put. I don't need something unbelievably awesome. Just something simple. If I just put in the following, it doesn't work.

PHP Code:

INSERT INTO tablename (field1, field2, field3) VALUES ('', '', ''); 


So I need to know how to run queries like vBulletin does it.