title: how to delete records from several child tables in the same query
body: <p>I ve got a database modelize like this,
  One mother table let's call it table_mother, and severals child tables.
  Relation beetween table_mother and childs is like this:</p>
  
  <p>All tables childs have a foreign key kind of name as the id of the mother table (id_table_mother) (relationship is 1->n as id_table_mother is uniq and tbale child can get several entries for id_table_mother)</p>
  
  <p>I would like to delete all records in childs table wich are related no more with the mother table, for now i try something like this</p>
  
  <pre><code>           DELETE FROM tb_child_1,tb_child_2,tb_child_3
                WHERE 
  tb_child_1.id_table_mother 
  AND tb_child_2.id_table_mother 
  AND tb_child_3.id_table_mother
                NOT IN (SELECT id_table_mother FROM tb_table_mother);
  </code></pre>
  
  <p>Thx</p>
  
  <p>edit : this is how I ended for now</p>
  
  <pre><code>delete from tb_child_1 where id_mother not in (select id_mother from tb_mother_table);
  delete from tb_child_2 where id_mother not in (select id_mother from tb_mother_table);
  </code></pre>
  
  <p>any "global" solution ?
  also my database is not innodb so I can 't go with foreigh keys and stuff</p>