I have this trigger:
delimiter $$ create trigger tr after update on t1 for each row begin if new.col1 !=old.col1 then update t2 set col2 =1 where t2.col3=t1.col3; end if; end $$
This trigger works when
col1's value changes from 0 to 1 but
when its changes from null to 1, the trigger doesn't make any changes in
I just wanted to know why it is so. I know null is different, but I'm just comparing the values.
I have solved my problem by doing