Building up a monthly total from past 12 months

Question

CurrentMonth = Month(CurrentDate)
CurrentYear = Year(CurrentDate)

    SQL = "SELECT Spent, MONTH(Date) AS InvMonth, YEAR(Date) As InvYear FROM Invoices WHERE YEAR(Date) = '" & CurrentYear & "' AND MONTH(Date) = '" & CurrentMonth & "'"
    RecordSet.Open SQL, Connection, adOpenStatic, adLockOptimistic, adCmdText
    Do Until RecordSet.EOF
        MTotal(i) = MTotal(i) + RecordSet.Fields("Spent")
        RecordSet.MoveNext
    Loop
    RecordSet.Close

This is the code I currently have to build up a total spent for a given month. I wish to expand this to retrieve the totals per month, for the past 12 months.

The way I see to do this would be to loop backwards through the CurrentMonth value, and if CurrentMonth value reaches 0 roll the value of CurrentYear back 1. Using the loop variable (i) to build up an array of 12 values: MTotal()

What do you guys think?

Answer 1

A group by should get you on the way.

SELECT TOP 12
  SUM(Spent) AS Spent
  , MONTH(Date) AS InvMonth
  , YEAR(Date) AS InvYear
FROM
  Invoices
GROUP BY
  YEAR(Date), MONTH(Date)
WHERE DATEDIFF(mm, Date, GETDATE(()) < 12

---

Josh's DATEDIFF is a better solution than my original TOP and ORDER BY

Answer 2

The only problem with this is that I require a monthly total, for each of the past 12 months rather then the total for the past 12 months. Otherwise I see how improving the SQL rather then using vb6 code oculd be a better option.

Answer 3

I would tackle this by "rounding" the date to the Month, and then Grouping by that month-date, and totalling the Spent amount:

 SELECT SUM(Spent) AS [TotalSpent],
        DATEADD(Month, DATEDIFF(Month, 0, [Date]), 0) AS [MonthDate]
 FROM   Invoices 
 WHERE      [Date] >= '20080301'
        AND [Date] <  '20090301'
 GROUP BY DATEADD(Month, DATEDIFF(Month, 0, [Date]), 0)
 ORDER BY [MonthDate]

The [MonthDate] can be formatted to show Month / Date appropraitely, or in separate columns.

The WHERE clause can be parameterised to provide a suitable range of records to be included

Answer 4

The solution I came up with would be :

For i = 0 To 11
    If CurrentMonth = 0 Then
        CurrentMonth = 12
        CurrentYear = CurrentYear - 1
    End If

    SQL = "SELECT Spent, MONTH(Date) AS InvMonth, YEAR(Date) As InvYear FROM Invoices WHERE YEAR(Date) = '" & CurrentYear & "' AND MONTH(Date) = '" & CurrentMonth & "'"
    RecordSet.Open SQL, Connection, adOpenStatic, adLockOptimistic, adCmdText
    Do Until RecordSet.EOF
        MTotal(i) = MTotal(i) + RecordSet.Fields("Spent").Value
        RecordSet.MoveNext
    Loop
    RecordSet.Close

    CurrentMonth = CurrentMonth - 1
Next

I believe this should work as expected. However I still look forward to seeing what solutions you guys can come up, or if anyone spots an issue with ym fix.