function get_meta_keys() {
	global $wpdb;

	$ignore1 = '_edit_last';
	$ignore2 = '_edit_lock';
	$ignore3 = '_wp_page_template';
	$ignore4 = '_wp_attached_file';
	$ignore5 = '_wp_attachment_metadata';

	$keys = $wpdb->get_col("SELECT meta_key FROM $wpdb->postmeta");
	$values = $wpdb->get_col("SELECT meta_value FROM $wpdb->postmetavalue");

	foreach ( $keys as $field ) {
		if(
			$field !== $ignore1 &&
			$field !== $ignore2 &&
			$field !== $ignore3 &&
			$field !== $ignore4 &&
			$field !== $ignore5) {
				echo $values. ' <br /> ' .$field;
			}
	}
}
get_meta_keys();