MySQL multi table joint deletion

  delete from  A WHERE A.name in (SELECT name FROM B WHERE TIMESTAMPDIFF(DAY,time,NOW()) >= 30);//B The inserted data in the table is more than 30 days compared with the current time ,, Delete A The corresponding data in the table 
        delete from  C WHERE C.task_name in (SELECT name FROM B WHERE TIMESTAMPDIFF(DAY,time,NOW()) >= 30);//B The inserted data in the table is more than 30 days compared with the current time ,, Delete C The corresponding data in the table 
delete from B where TIMESTAMPDIFF(DAY,time,NOW()) >= 30);