Can I temporarily store a value in the Select Statement of SQL?

Question

In my select statement, I have two returns that are calculations. It looks like this:

 SELECT
     a.FormRate AS 'F-Rate'
     ,a.LoI AS 'Liability'
     ,CAST((A.FormRate * a.LoI / 100) AS DECIMAL(38,2)) 'F-Premium'
     ,a.EndorsementRate AS 'E-Rate'
     ,CAST((A.EndorsementRate * a.LoI / 100) AS DECIMAL(38,2)) 'E-Premium' 

FROM tblAspecs a

Once I have those five statements in the select, I'd like to be able to total E-Premium + F-Premium into a new column. I could always do it this way:

  ,CAST(((A.EndorsementRate * a.Loi / 100) + (a.FormRate * a.LoI / 100)) AS DECIMAL(38,2)) 'Total Premium'

...but that just just seems to be quite sloppy and bulky. Is there a way to store the individual premiums so that I can just do a simple CAST((F-Premium + E-Premium) AS DECIMAL(38,2)) 'Total Premium'

The bulky way also doesn't leave F-Premium and E-Premium dynamic so that if I ever change how they're calculated, I'd have to also change the calculation in the Total Premium column.

Using Microsoft SQL Server Management Studio 2010

Answer 1

Research Common Table Expressions.

It will look something like this:

;WITH [Data]
(
    [FormRate],
    [Liability],
    [FormPremium],
    [EndorsementRate],
    [EndorsementPremium]
)
AS
(
    SELECT
         a.[FormRate],
         a.[LoI] AS [Liability],
         CAST((a.[FormRate] * a.[LoI] / 100) AS DECIMAL(38,2)),
         a.[EndorsementRate],
         CAST((a.[EndorsementRate] * a.[LoI] / 100) AS DECIMAL(38,2)) 
    FROM 
        tblAspecs a
)
SELECT
    [Data].*,
    CAST(([Data].[FormPremium] + [Data].[EndorsementPremium]) AS DECIMAL(38,2)) 'Total Premium'
FROM
    [Data]