SQL 2005 If Statement some help please

[chapo]

I'm new to SQL 2005 and would greatly appreciate some help in the following problem.

I have two tables joint by the ID field
In table one I have the following fields Sequence, Quan and ID.
In table two I have Quan and ID

Here is what I would like if possible.

If Sequence is = Null then show me the Quan value from table 2 else show me the Quan value from table 1.

[nosepicker]

SELECT
CASE WHEN Table1.Sequence IS NULL THEN Table2.Quan
ELSE Table1.Quan END
FROM Table1 JOIN Table2
ON Table1.ID = Table2.ID

[chapo]

Thank you