I'm still not able to understand what you want to do here.

If you had one record per Calendar_Month, this would make more sense to me. As it is, you have a lot of them, with no apparent way to sort them. So I'm guessing you want to somehow SUM your columns and group by Calendar_Month or something? If so, you would want to use that as your starting point and then do something like this:

-- This would have to have one record per Calendar_Month to work:

WITH A AS

(

SELECT *, RN = ROW_NUMBER() OVER(ORDER BY Calendar_Month) FROM #TrialBalance

)

SELECT

A.Trial_Balance_ID,

A.FISCALYEAR,

A.Calendar_Month,

A.actindx,

A.CATEGORY,

A.POSTINGTYPE,

A.ACTIVITYDEBIT,

A.ACTIVITYCREDIT,

A.NETAMOUNT,

A.Trial_Balance_Debit,

A.Trial_Balance_Credit,

A.Trial_Balance_Net,

ISNULL(B.Trial_Balance_Debit, 0) AS Beginning_Balance_Debit,

A.Beginning_Balance_Credit,

A.Beginning_Balance_Net

FROM A

LEFT OUTER JOIN A AS B ON

A.RN - 1 = B.RN

ORDER BY A.Calendar_Month