MySQL 8.0

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.

CREATE TABLE `adresses` (
  `adress_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `street` varchar(200) NOT NULL,
  `house_number` varchar(6) NOT NULL,
  `postal_code` smallint(5) unsigned NOT NULL,
  `city` varchar(100) NOT NULL,
  PRIMARY KEY (`adress_id`),
  KEY `street` (`street`),
  KEY `postal_code` (`postal_code`),
  KEY `city` (`city`)
) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8;

/*Data for the table `adresses` */

insert  into `adresses`(`adress_id`,`street`,`house_number`,`postal_code`,`city`) values 
(1,'first','1',12345,'London'),
(2,'second','2',23456,'Paris'),
(3,'third','3',34567,'Okawa'),
(4,'fourth','4',45678,'Berlin'),
(5,'fiveth','5',56789,'ABCDE'),
(6,'sixth','6',65535,'DFGHJH');

/*Table structure for table `persons` */

CREATE TABLE `persons` (
  `person_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(50) NOT NULL,
  PRIMARY KEY (`person_id`),
  KEY `name` (`name`)
) ENGINE=InnoDB AUTO_INCREMENT=9 DEFAULT CHARSET=utf8;

/*Data for the table `persons` */

insert  into `persons`(`person_id`,`name`) values 
(1,'Anna'),
(2,'John'),
(3,'Michel'),
(4,'Olivia'),
(5,'Pavel'),
(6,'Peter'),
(7,'Sarah'),
(8,'Tobias');

/*Table structure for table `tasks` */

CREATE TABLE `tasks` (
  `task_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `person_id` int(10) unsigned NOT NULL,
  `adress_id` int(10) unsigned NOT NULL,
  `description` varchar(200) NOT NULL,
  PRIMARY KEY (`task_id`),
  KEY `person_id` (`person_id`),
  KEY `adress_id` (`adress_id`)
) ENGINE=InnoDB AUTO_INCREMENT=8 DEFAULT CHARSET=utf8;

/*Data for the table `tasks` */

insert  into `tasks`(`task_id`,`person_id`,`adress_id`,`description`) values 
(1,1,2,''),
(2,2,3,''),
(3,3,4,''),
(4,5,6,''),
(5,4,1,''),
(6,1,4,''),
(7,3,3,''),
(8,8,1,'');

SELECT
  tasks.task_id
FROM
  (
    tasks,
    (SELECT
      adress_id AS id,
      'adress_id' AS typ
    FROM
      adresses
    WHERE adresses.city LIKE 'tobias%'
      OR adresses.street LIKE 'tobias%'
    UNION
    SELECT
      person_id AS id,
      'person_id' AS typ
    FROM
      persons
    WHERE persons.name LIKE 'tobias%') f0,
    (SELECT
      adress_id AS id,
      'adress_id' AS typ
    FROM
      adresses
    WHERE adresses.city LIKE 'london%'
      OR adresses.street LIKE 'london%'
    UNION
    SELECT
      person_id AS id,
      'person_id' AS typ
    FROM
      persons
    WHERE persons.name LIKE 'london%') f1
  )
WHERE (
    f0.typ = 'adress_id'
    AND tasks.adress_id = f0.id
    OR f0.typ = 'person_id'
    AND tasks.person_id = f0.id
  )
  AND (
    f1.typ = 'adress_id'
    AND tasks.adress_id = f1.id
    OR f1.typ = 'person_id'
    AND tasks.person_id = f1.id
  )

task_id
8