gistfile1.php

<?php 
function ebs_seo_cp_sort_columns( $vars ) {

  if ( isset( $vars['post_type'] ) && 'location' == $vars['post_type'] ) {

		if ( isset( $vars['orderby'] ) ) {
		
			switch ($vars['orderby'] ) {
				case 'street' :
					$vars = array_merge(
						$vars,
						array(
							'meta_key' => 'street',
							'orderby' => 'meta_value'
						)
					);
					break;
				case 'city' :
					$vars = array_merge(
						$vars,
						array(
							'meta_key' => 'city',
							'orderby' => 'meta_value'
						)
					);
					break;
				case 'state' :
					$vars = array_merge(
						$vars,
						array(
							'meta_key' => 'state',
							'orderby' => 'meta_value'
						)
					);
					break;
				case 'zip' :
					$vars = array_merge(
						$vars,
						array(
							'meta_key' => 'zip',
							'orderby' => 'meta_value_num'
						)
					);
					break;
			}

		}
	}

	return $vars;
}