Exclude a user field from usermeta search

my_pmpro_member_sql_search_where.php

<?php
/**
 * Filter directory search conditions to exclude a specific field from usermeta search
 *
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */

function my_pmpro_member_sql_search_where( $sql_search_where, $s ) {

	$sql_search_where = "
		AND (
			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 ) . "%' AND um.meta_key != 'field_name' )
		)
	";
	
	return $sql_search_where;
}
add_filter( 'pmpro_member_directory_sql_search_where', 'my_pmpro_member_sql_search_where', 10, 2 );

Exclude multiple fields: https://gist.github.com/dwanjuki/a09689da0e1076aa7ee540d7b0732d25