Multiple Action Trigger in MySQL 5.0.45?

Hello everyone:

I’m working in phpMyAdmin and I’m new to creating MySQL triggers. I’m trying to create a trigger that will help me validate data by throwing an error when a value it out of range.

This works just fine:

create trigger t1
    before insert
    on hvi
    for each row
    begin
    declare dummy int;
    if new.`Moist (dry%)` <1 then
    select `Moist(dry%) cannot be less than 1`
    into dummy
    from hvi
    where id = new.`Moist (dry%)`;
    end if;
    end;

But I need to add more actions to this trigger. I tired this:

create trigger t1
    before insert
    on hvi
    for each row
    begin
    declare dummy int;
    if new.`Moist (dry%)` <1 then
    select `Moist(dry%) cannot be less than 1`
    into dummy
    from hvi
    where id = new.`Moist (dry%)`;
    end if;
    if new.`Moist (dry%)` >50 then
    select `Moist(dry%) cannot be greater than 50`
    into dummy
    from hvi
    where id = new.`Moist (dry%)`;
    end if;
    end;

but it returned this error "#1235 - This version of MySQL doesn’t yet support ‘multiple triggers with the same action time and event for one table’ "

Does anyone know how I can add multiple actions to a trigger? (Multiple if-then statements? I’ll eventually need to add about 20.)

Thanks!