Help Needed With DATETIME Arithmetic

Hi,

I have the following query:

SELECT dbo._Fault.id, dbo._Fault.date_created, dbo._Fault.reference,
dbo._Fault.class, dbo._Fault.owner, dbo._Fault.Contact_Name, dbo._Fault.
Product,
dbo._Fault.Problem_Description,
dbo._Fault.Action_Taken, dbo._Fault.Problem_Solution,
dbo._Fault.Duration_start_date, dbo._Fault.Duration_duration,
dbo._Fault.Duration_date_summary,
dbo._Fault.Fault_Status, dbo._Fault.Fault_Source, dbo._Fault.Part_Number,
dbo._Fault.Serial_No,
dbo._Product.id AS PRODUCTID, dbo._Product.description
FROM dbo._Fault LEFT OUTER JOIN
dbo._Product ON dbo._Fault. Product = dbo._Product.id

I need an additional field appended to the end of this (called
'DATECOMPLETED') that will take the 'Duration_start_date' and add the
'Duration_duration' to it - effectively giving me a new datetime field that
is newer than the start date.

I have tried unseccessfully to amend the code but I am afraid my knowledge
of SQL is limited. I would greatly appreciate if someone could show me how
to do this.

Thanks,

Darren