MySQL automatic update for specific column instead of whole record

Question

I have a table APPLEVARIETY. It has the following columns:

• id
• family
• color
• description (TEXT)
• description_last_update_time (TI

Answer 1

No thats not possible using the ON UPDATE CURRENT_TIMESTAMP this will get updated when any column is updated. You may however achieve the same using a trigger. For that you will first need to remove ON UPDATE CURRENT_TIMESTAMP from the table definition. The trigger will look like

delimiter //

create trigger APPLEVARIETY_update before update on APPLEVARIETY
for each row 
begin
  if new.description <> old.description then
    set new.description_last_update_time = now();
  end if;
end;//

delimiter ;