Question : SQL 2008 - Need to use calcualted field in another calculation

I need to use a calculated field in a query in another area of the same query.  I have

SUM(tbl_nav_now - nav_past) AS Change,  and I tried the following

Sum(Change / tbl_nav_now) AS Percent but it did not like it.  What would be the correct syntax with rounding?

Any help is appreciated.

Answer : SQL 2008 - Need to use calcualted field in another calculation

are you ignoring my post?

Sum(Change / tbl_nav_now) AS Percent
-->
Sum((tbl_nav_now - nav_past) / tbl_nav_now) AS Percent

if you exactly want x.xx format you should use cast

Cast(Sum((tbl_nav_now - nav_past) / tbl_nav_now), decimal(10,2)) AS Percent