ScottPletcher (9/3/2013)
You don't want to use a function against the END_DATETIME column if you can avoid it, since any function will prevent SQL from using the full seek capabilities against that column in any index(es) in which it might appear.I think the code below will do SELECT the same rows as your original query, but adjust the code if/as needed to match you need:
SELECT *
FROM dbo.tablename
WHERE
END_DATETIME >= DATEADD(HOUR, -@tzoffset, @StartDate) AND
END_DATETIME <= DATEADD(HOUR, -@tzoffset, @EndDate)
Same thing I suggested in my post.