<p>I have a <code>datetime</code> column in MySQL. </p>

<p>How can I convert it to the display as <strong>mm/dd/yy H:M (AM/PM)</strong> using PHP?</p>

An easier way would be to format the date directly in the MySQL query, instead of PHP.  See the
MySQL manual entry for DATE_FORMAT
.
If you'd rather do it in PHP, then you need the
date
function, but you'll have to convert your database value into a timestamp first.