-- REMOVE OLD TABLES
DROP TABLE IF EXISTS test_machine;
DROP TABLE IF EXISTS test_order;

-- CREATE 
CREATE TABLE IF NOT EXISTS `test_machine` (
  `machineid` VARCHAR(32) NOT NULL,
  `activeorderid` bigint(20) unsigned DEFAULT NULL,
  PRIMARY KEY (`machineid`)
) ENGINE=InnoDB;

REPLACE INTO `test_machine` (`machineid`, `activeorderid`) 
    VALUES ('m1', NULL), ('m2', 2), ('m3', NULL), ('m4', NULL);

CREATE TABLE IF NOT EXISTS `test_order` (
  `orderid` bigint(20) unsigned NOT NULL,
  `machineid` VARCHAR(32) DEFAULT NULL,
  PRIMARY KEY (`orderid`)
) ENGINE=InnoDB;

INSERT IGNORE INTO `test_order` (`orderid`, `machineid`) 
    VALUES (1, 'm2'), (2, 'm2');

-- Query

SELECT test_order.*,'|' as sep, test_machine.* FROM test_order LEFT JOIN test_machine ON (test_machine.machineid=test_order.machineid AND test_machine.activeorderid=test_order.orderid);