Trigger to update a value

[Paul Grimes]

Hi All.
I have a table called material and in here I have the following
id (key and AI)
Title
Job_No
Quantity
Unit_Price
TotalLineValue

When I add items it basically multiply's the Quantity by the Unit Price and puts it in the TotalLineValue

I also have a table called a
In this I have the following
id (key and AI)
Job_No
MatTot

And i have this trigger

CREATE TRIGGER `NewTrigger` AFTER INSERT ON `material`
FOR EACH ROW UPDATE new_db_2005.a
SET a.MatTot =
(SELECT SUM(TotalLineValue)
FROM material
WHERE Job_No = a.Job_No)
WHERE a.id = NEW.id

So when a new value is added to the materials it will update the MatTot in table a where the Job_No is the same?

Is this possible?

Thanks