Wordpress question - how to add a field into wp-admin/post-new.php

Hi to everyone . I want to add a new field in wp-admin/post-new.php and when I press publish button a query to be submitted . Can you help me with some syntax or ideas to do that ?

I need two things to know and after I'm able to finish my work .
1. How can I add a field into wp-admin/post-new.php (bellow the content writer field )
2. How can I write a function like this: <?php if(is_publish(){ $sql = mysql_query( my query ) } ?> to determine when the button publish is pressed .

P.S: I don't want to use custom_fields because I want to insert things in another table than wp_terms .

Thanks,
puya4ever.

 

you can use current time stamp of sql to implement this feature imo

 

I don't understand . Which are the current time stamp of sql ?