Creating a trigger to update one table’s row based on another update from a different table’s row

So, I have the following two tables:

CREATE TABLE IF NOT EXISTS `services` (   `services_id` INT NOT NULL AUTO_INCREMENT,   `staff_num` INT NOT NULL,   `health_and_wellness` INT NOT NULL,   `tutoring` INT NOT NULL,   PRIMARY KEY (`services_id`),   UNIQUE INDEX `services_id_UNIQUE` (`services_id` ASC) VISIBLE,   INDEX `fk_services_healthandwell_idx` (`health_and_wellness` ASC) VISIBLE,   INDEX `fk_services_tutoring_idx` (`tutoring` ASC) VISIBLE,   CONSTRAINT `fk_services_tutoring`     FOREIGN KEY (`tutoring`)     REFERENCES `tutoring` (`tutoring_id`)     ON DELETE CASCADE     ON UPDATE CASCADE,   CONSTRAINT `fk_services_healthandwell`     FOREIGN KEY (`health_and_wellness`)     REFERENCES `health and wellness` (`health_and_wellness_id`)     ON DELETE CASCADE     ON UPDATE CASCADE) ENGINE = InnoDB; 

and

CREATE TABLE IF NOT EXISTS `tutoring` (   `tutoring_id` INT NOT NULL AUTO_INCREMENT,   `subject` INT NOT NULL,   `staff_members` INT NOT NULL,   PRIMARY KEY (`tutoring_id`),   UNIQUE INDEX `tutoring_id_UNIQUE` (`tutoring_id` ASC) VISIBLE,   INDEX `fk_tutoring_subject_idx` (`subject` ASC) VISIBLE,   CONSTRAINT `fk_tutoring_subject`     FOREIGN KEY (`subject`)     REFERENCES `subjects` (`subject_id`)     ON DELETE NO ACTION     ON UPDATE NO ACTION) ENGINE = InnoDB; 

I want to create a trigger that updates services.staff_num whenever tutoring.staff_members is updated.. I’ve tried a couple different triggers, but each time nothing happens or I get an error.. My latest attempt was this:

DELIMITER $  $   CREATE TRIGGER UpdateStaffNum AFTER UPDATE ON collegedb.tutoring FOR EACH ROW     BEGIN         UPDATE services         SET services.staff_num = services.staff_num + tutoring.staff_members;  END; 

Which of course would be too simple too work, heh. Anyone have any suggestions on this? Thanks.