php - Mysql Trigger not working while updating history table -

php - Mysql Trigger not working while updating history table -

i want update history table using below trigger

create trigger `trig_update_transaction` after update on `transaction` each row begin update transaction_history set old.deliverystatus=new.deliverystatus old.alertid=new.alertid; end$$

what problem here?

problem in these lines:

update transaction_history set old.deliverystatus = new.deliverystatus old.alertid=new.alertid;

from mysql documentation: in update trigger, can utilize old.col_name refer columns of row before updated , new.col_name refer columns of row after updated.

a column named old read only. can refer (if have select privilege), not modify it.

for details, refer this

i love read community on this.

php mysql triggers