Access get value from previous record

问题

I have an Access query with the following

GL_A.Account, 
GL_P.FiscalYear, 
GL_P.FiscalPeriod, 
GL_P.BeginningBalance, 
GL_P.DebitAmount, 
GL_P.CreditAmount, 
[BeginningBalance]+([DebitAmount]-[CreditAmount]) AS EndingBalance

The problem is that BeginningBalance only has values for January (FiscalPeriod 1).

I need to have a new field ActualBeginngBal which comes from the previous month EndingBalance (Except January)

Note: there are many account #'s but each account only has 1 record per FiscalPeriod/FiscalYear

Your help would be greatly appreciated,
Thank you

回答1:

See if this helps. Put a 2nd copy of the table in the query, joined to the 1st copy on Account and FiscalYear but not on FiscalPeriod. Then the ActualBeginningBalance can be calculated from the 2nd copy of the table with a constraint to select only FiscalPeriod < the FiscalPeriod from the 1st table. Note - you may get a null results for January, which you may need to convert to a 0.

OK, it's a bit more complicated - I did end up using a subquery similar to the other response, but calculated the EB instead of trying to pull it from the table

SELECT Ledger.Account, Ledger.FiscalYear, Ledger.FiscalPeriod, 
[BeginningBalance]+
       IIf([FiscalPeriod]<>"01",
             (select sum(T.BeginningBalance+T.DebitAmount-T.CreditAmount) 
             from Ledger T 
              where T.account=Ledger.account and T.FiscalYear=Ledger.FiscalYear and T.FiscalPeriod<Ledger.FiscalPeriod)
        ,0) 
       AS ActualBeginningBalance, 
Ledger.DebitAmount AS DebitAmount, 
Ledger.CreditAmount AS CreditAmount, 
[ActualBeginningBalance]+[DebitAmount]-[CreditAmount] AS EndingBalance
FROM Ledger;

回答2:

This SQL does the job and returns the table below (with my test data):

SELECT    T1.Account
        , T1.FiscalYear
        , T1.FiscalPeriod
        , T1.ActualBeginngBal
        , (
           SELECT TOP 1 T2.EndingBalance
           FROM   Table1 T2
           WHERE CLNG(T2.FiscalYear & Format(T2.FiscalPeriod,"00")) <
                 CLNG(T1.FiscalYear & Format(T1.FiscalPeriod,"00")) AND
                 T2.Account = T1.Account
           ORDER BY CLNG(T2.FiscalYear & Format(T2.FiscalPeriod,"00")) DESC
           ) AS BeginningBalance
        , T1.EndingBalance
FROM    Table1 T1

回答3:

IT WOULD BE BETTER IF YOU USE BeginningBalance in primary table. Because it is only one record belong to one account. it is one to one relationship.

来源：https://stackoverflow.com/questions/42629523/access-get-value-from-previous-record

标签

ms-access