Sort meta-field company for PMPro member directory | original: https://gist.github.com/greathmaster/4f2ba4304e4f2584738691fcd0c7c2ce

pmpro-custom-member-directory-sort.php

<?php
/**
 * Sort meta-field company for PMPro member directory
 *
 * @param  [type] $sqlQuery [description]
 * @param  [type] $levels   [description]
 * @param  [type] $s        [description]
 * @param  [type] $pn       [description]
 * @param  [type] $limit    [description]
 * @param  [type] $start    [description]
 * @param  [type] $end      [description]
 * @param  [type] $order_by [description]
 * @param  [type] $order    [description]
 *
 * @return [type]           [description]
 */
function my_pmpro_member_directory_sql( $sqlQuery, $levels, $s, $pn, $limit, $start, $end, $order_by, $order ) {
	  global $wpdb;

	if ( $s ) {
		$sqlQuery =

		"SELECT SQL_CALC_FOUND_ROWS 
		  u.ID, 
		  u.user_login, 
		  u.user_email, 
		  u.user_nicename, 
		  u.display_name, 
		  UNIX_TIMESTAMP(u.user_registered) as joindate, 
		  mu.membership_id, 
		  mu.initial_payment, 
		  mu.billing_amount, 
		  mu.cycle_period, 
		  mu.cycle_number, 
		  mu.billing_limit, 
		  mu.trial_amount, 
		  mu.trial_limit, 
		  UNIX_TIMESTAMP(mu.startdate) as startdate, 
		  UNIX_TIMESTAMP(mu.enddate) as enddate, 
		  m.name as membership, 
		  umf.meta_value as first_name, 
		  uml.meta_value as last_name,
		  umz.meta_value as company
		  
		  FROM $wpdb->users u 
		  
		  LEFT JOIN $wpdb->usermeta umh ON umh.meta_key = 'pmpromd_hide_directory' AND u.ID = umh.user_id 
		  LEFT JOIN $wpdb->usermeta umf ON umf.meta_key = 'first_name' AND u.ID = umf.user_id 
		  LEFT JOIN $wpdb->usermeta uml ON uml.meta_key = 'last_name' AND u.ID = uml.user_id 
		  LEFT JOIN $wpdb->usermeta umz ON umz.meta_key = 'company' AND u.ID = umz.user_id 
		  LEFT JOIN $wpdb->usermeta um ON u.ID = um.user_id 
		  LEFT JOIN $wpdb->pmpro_memberships_users mu ON u.ID = mu.user_id 
		  LEFT JOIN $wpdb->pmpro_membership_levels m ON mu.membership_id = m.id 
				  
		  WHERE mu.status = 'active' 
		  AND (umh.meta_value IS NULL OR umh.meta_value <> '1') 
		  AND mu.membership_id > 0 AND ";

		$sqlQuery .= "(u.user_login LIKE '%" . esc_sql( $s ) . "%' OR u.user_email LIKE '%" . esc_sql( $s ) . "%' OR u.display_name LIKE '%" . esc_sql( $s ) . "%' OR um.meta_value LIKE '%" . esc_sql( $s ) . "%') ";
		if ( $levels ) {
			$sqlQuery .= ' AND mu.membership_id IN(' . esc_sql( $levels ) . ') ';
		}
		$sqlQuery .= 'GROUP BY u.ID ORDER BY ' . esc_sql( $order_by ) . ' ' . $order;
	} else {
		$sqlQuery =

		"SELECT SQL_CALC_FOUND_ROWS u.ID, 
		  u.user_login, 
		  u.user_email, 
		  u.user_nicename, 
		  u.display_name, 
		  UNIX_TIMESTAMP(u.user_registered) as joindate, 
		  mu.membership_id, 
		  mu.initial_payment, 
		  mu.billing_amount, 
		  mu.cycle_period, 
		  mu.cycle_number, 
		  mu.billing_limit, 
		  mu.trial_amount, 
		  mu.trial_limit, 
		  UNIX_TIMESTAMP(mu.startdate) as startdate, 
		  UNIX_TIMESTAMP(mu.enddate) as enddate, 
		  m.name as membership, 
		  umf.meta_value as first_name, 
		  uml.meta_value as last_name,
		  umz.meta_value as company
   
		  
		  FROM $wpdb->users u 
		  
		  LEFT JOIN $wpdb->usermeta umh ON umh.meta_key = 'pmpromd_hide_directory' AND u.ID = umh.user_id 
		  LEFT JOIN $wpdb->usermeta umf ON umf.meta_key = 'first_name' AND u.ID = umf.user_id 
		  LEFT JOIN $wpdb->usermeta uml ON uml.meta_key = 'last_name' AND u.ID = uml.user_id 
		  LEFT JOIN $wpdb->usermeta umz ON umz.meta_key = 'company' AND u.ID = umz.user_id 
		  LEFT JOIN $wpdb->pmpro_memberships_users mu ON u.ID = mu.user_id 
		  LEFT JOIN $wpdb->pmpro_membership_levels m ON mu.membership_id = m.id";

		$sqlQuery .= " 
		WHERE mu.status = 'active' 
		AND (umh.meta_value IS NULL OR umh.meta_value <> '1') 
		AND mu.membership_id > 0 ";
		if ( $levels ) {
			$sqlQuery .= ' AND mu.membership_id IN(' . esc_sql( $levels ) . ') ';
		}
		$sqlQuery .= 'ORDER BY ' . esc_sql( $order_by ) . ' ' . esc_sql( $order );
	}
	  $sqlQuery .= " LIMIT $start, $limit";

	  return $sqlQuery;
}

  add_filter( 'pmpro_member_directory_sql', 'my_pmpro_member_directory_sql', 10, 9 );