mysql - query three tables

Question

I have a relational database with three tables. The first containts id\'s that relate to the second. The second contains id\'s that relate to the third. The third contains the r

Answer 1

you want to use a join:

   SELECT `t3`.`id`
     FROM `table3` `t3`
LEFT JOIN `table2` `t2`
       ON `t3`.`foreign_id` = `t2`.`id`
LEFT JOIN `table1` `t1`
       ON `t2`.`foreign_id` = `t1`.`id`
    WHERE `t1`.`id` = 'some_id'