read_mysql_one_value(MYSQL *connection, const char *query)
{
	MYSQL_RES *mysql_result;
	MYSQL_ROW row;
	char *result = NULL;

	mysql_result = xb_mysql_query(connection, query, true);

	ut_ad(mysql_num_fields(mysql_result) == 1);

	if ((row = mysql_fetch_row(mysql_result))) {
		result = strdup(row[0]);
	}

	mysql_free_result(mysql_result);

	return(result);
}