Generating a Numerical number for Date Difference

I am trying to calculate the difference between two dates, however I cannot seem to get a viable response when subtracting the two numbers.

The SQL is:
Select
p.Name
, p.ProjectStatus
, (Select u.UDFDate AS GoLive FROM UDFdate as u
WHERE u.Itemname = 'ProjectText9'
AND u.EntityID = CAST(p.ProjectID AS uniqueidentifier)) AS GoLive
, (Select u.UDFDate AS SOW_GoLive FROM UDFdate as u
WHERE u.Itemname = 'ProjectText19'
AND u.EntityID = CAST(p.ProjectID AS uniqueidentifier)) AS SOW_GoLive


, ((Select u.UDFDate AS GoLive FROM UDFdate as u
WHERE u.Itemname = 'ProjectText9'
AND u.EntityID = CAST(p.ProjectID AS uniqueidentifier)) -
(Select u.UDFDate AS SOW_GoLive FROM UDFdate as u
WHERE u.Itemname = 'ProjectText19'
AND u.EntityID = CAST(p.ProjectID AS uniqueidentifier))) AS DIFF


FROM Project as p
INNER JOIN
UDFdate as u on p.ProjectID = u.EntityID
WHERE p.Deleted=0
AND p.ProjectStatus = 'A'
AND NOT((Select u.UDFDate AS SOW_GoLive FROM UDFdate as u
WHERE u.Itemname = 'ProjectText19'
AND u.EntityID = CAST(p.ProjectID AS uniqueidentifier)) is NULL)
GROUP BY p.Name, p.ProjectID, p.ProjectStatus


The Column DIFF shows up as YYYY-MM-DD HH:MM:SS.000

Any suggestions how I can convert the DIFF to be a ##?

You should be able to use DateDiff.

....
,DateDiff("d", (SELECT u.UDFDate AS golive ....), (SELECT u.UDFDate AS SOW_GoLive ...)) AS DIFF
....


Here's a link to info on DateDiff

http://msdn2.microsoft.com/en-us/library/aa258269(SQL.80).aspx