Proper procedure to close mysql queries!

Hi, Just need some mailing list input here, what is the proper way to close a mysql query using PHP. - What is the proper way to close a php query to mysql if one query is in the file? - What is the proper way to close a php query to mysql if 2 or more queries is in the file and where do you close it off? So if I use <? code here ?> or <?php code here ?> is that a safe way to do it and does this close the mysql session off or does it timeout after a set period of time? Or is a better way mysql_close()? Or do both work the same? Thanks! J