At 11:50 PM 3/11/2003 +0000, you wrote:

>Hi helen. But I dont have a null value on the table A request field.

It will be the same if new.request is null. Value + null always produces null.

>Do you have any idea why this happen? I have been using this for about
>3-4 month and it happen a few times where the trigger seems have not
>triggered.

The trigger always fires. If you don't see the expected result, then
something is wrong with your expectation - all you can do is test more
until you find out which wrong assumption is causing the unexpected result.

Do you understand that, if the operation on Table B fails and you roll back
the transaction, then anything done by triggers also gets rolled back?

heLen