Trailing Twelve Month Formula using MS Access Database - sql

Question

I have a database named Cash_Flow_Statements and I need to create a saved query that calculates a Trailing Twelve Month (TTM) Free Cash Flow.
Here is an example of my database:
And here is the code for my saved query. I have used this code for other calculations so I know it works. I just don't know how to do a Trailing Twelve Month in SQL.
CREATE PROC " & Calculation & " AS _
SELECT Income_Statements.Ticker, Income_Statements.[Year], Income_Statements.Period, _
" & Formula & " AS TTM _
FROM (Income_Statements AS Income_Statements INNER JOIN Balance_Sheets AS Balance_Sheets ON (Income_Statements.Ticker = Balance_Sheets.Ticker) AND (Income_Statements.[Year] = Balance_Sheets.[Year]) AND (Income_Statements.Period = Balance_Sheets.Period)) _
INNER JOIN Cash_Flow_Statements AS Cash_Flow_Statements ON (Balance_Sheets.Ticker = Cash_Flow_Statements.Ticker) AND (Balance_Sheets.[Year] = Cash_Flow_Statements.[Year]) AND (Balance_Sheets.Period = Cash_Flow_Statements.Period)
I need the variable Formula to contain the equation that will calculate the Trailing Twelve Month for Free Cash Flow. Here is what the math looks like:
Free Cash Flow TTM = Sum(Operating Cash Flow MRQ1 + Operating Cash Flow MRQ2 + Operating Cash Flow MRQ3 + Operating Cash Flow MRQ4) - Sum(Capital Expenditures MRQ1 + Capital Expenditures MRQ2 + Capital Expenditures MRQ3 + Capital Expenditures MRQ4)
MRQ = Most Recent Quarter
I need this formula to be in SQL. How do I do this?
UPDATE
Per #Gord Thompson's answer below I have come up with this code:
SELECT Ticker, [Year], Period, (SELECT (SUM(su.Net_Cash_Flow_Operating) - SUM(su.Capital_Expenditures)) _
FROM (SELECT Ticker, [Year], Period, Net_Cash_Flow_Operating, Capital_Expenditures _
FROM Cash_Flow_Statements _
UNION ALL _
SELECT Ticker, [Year] + 1, Period - 4, Net_Cash_Flow_Operating, Capital_Expenditures _
FROM Cash_Flow_Statements) su _
WHERE su.Ticker = s.Ticker AND su.[Year] = s.[Year] AND (su.Period Between s.Period - 3 And s.Period)) _
AS SalesLast12Months _
FROM Cash_Flow_Statements AS s
When this is run by itself it returns exactly what I need. But as I mentioned in my original post I need to be able to set the variable Formula to contain the SQL statement and then insert it into the existing SQL statement.
So I've tried to adapt #Gord Thompson answer and I've come up this this.
Formula:
Formula = “(SELECT (SUM(su.Net_Cash_Flow_Operating) - SUM(su.Capital_Expenditures)) _
FROM (SELECT Ticker, [Year], Period, Net_Cash_Flow_Operating, Capital_Expenditures _
FROM Cash_Flow_Statements UNION ALL SELECT Ticker, [Year] + 1, Period - 4, Net_Cash_Flow_Operating, Capital_Expenditures _
FROM Cash_Flow_Statements) su _
WHERE su.Ticker = Cash_Flow_Statements.Ticker AND su.[Year] = Cash_Flow_Statements.[Year] AND (su.Period Between Cash_Flow_Statements.Period - 3 And Cash_Flow_Statements.Period))”
SQL statement:
"CREATE PROC " & Calculation & " AS SELECT Income_Statements.Ticker, Income_Statements.[Year], Income_Statements.Period, " & Formula & " AS TTM _
FROM (Income_Statements AS Income_Statements _
INNER JOIN Balance_Sheets AS Balance_Sheets ON (Income_Statements.Ticker = Balance_Sheets.Ticker) AND (Income_Statements.[Year] = Balance_Sheets.[Year]) AND (Income_Statements.Period = Balance_Sheets.Period)) _
INNER JOIN Cash_Flow_Statements AS Cash_Flow_Statements ON (Balance_Sheets.Ticker = Cash_Flow_Statements.Ticker) AND (Balance_Sheets.[Year] = Cash_Flow_Statements.[Year]) AND (Balance_Sheets.Period = Cash_Flow_Statements.Period)
This is the result:
Again this is very close but not quite what I need. I believe that I know what causes the code to not work when I adapt it but I don't know how to fix it yet. In #Gord Thompson code the last line is FROM Cash_Flow_Statements AS s. When I insert the variable formula into my existing SQL statement from my original post, the code is FROM (Income_Statements AS Income_Statements _
INNER JOIN Balance_Sheets AS Balance_Sheets ON (Income_Statements.Ticker = Balance_Sheets.Ticker) AND (Income_Statements.[Year] = Balance_Sheets.[Year]) AND (Income_Statements.Period = Balance_Sheets.Period)) _
INNER JOIN Cash_Flow_Statements AS Cash_Flow_Statements ON (Balance_Sheets.Ticker = Cash_Flow_Statements.Ticker) AND (Balance_Sheets.[Year] = Cash_Flow_Statements.[Year]) AND (Balance_Sheets.Period = Cash_Flow_Statements.Period). I'm almost positive that this is where the problems lies but do not know how to correct it.

Answer 1

Let's not get too hung up on the columns, let's concentrate on selecting the appropriate rows.
Say we had a table named [SalesSummary] containing
Item FiscalYear Quarter TotalSales
-------- ---------- ------- ----------
bicycles 2011 1 100
bicycles 2011 2 200
bicycles 2011 3 300
bicycles 2011 4 400
bicycles 2012 1 500
bicycles 2012 2 600
bicycles 2012 3 700
bicycles 2012 4 800
ham 2011 1 10
ham 2011 2 20
ham 2011 3 30
ham 2011 4 40
ham 2012 1 50
ham 2012 2 60
ham 2012 3 70
ham 2012 4 80
If we wanted to create a query that showed the quarterly figures along with the total sales for the past 12 months (current quarter plus the previous 3 quarters) one might think that we would have to start messing around with IIf() to handle the "wrap around" from one FiscalYear to the next. Fortunately, we don't, because we can just replicate the same data with "fake" quarters for the next FiscalYear: 2011_Q(4) becomes 2012_Q(0), 2011_Q(3) becomes 2012_Q(-1), and so on.
SELECT
Item,
FiscalYear,
Quarter,
TotalSales
FROM SalesSummary
UNION ALL
SELECT
Item,
FiscalYear + 1,
Quarter - 4,
TotalSales
FROM SalesSummary
returns
Item FiscalYear Quarter TotalSales
-------- ---------- ------- ----------
bicycles 2011 1 100
bicycles 2011 2 200
bicycles 2011 3 300
bicycles 2011 4 400
bicycles 2012 1 500
bicycles 2012 2 600
bicycles 2012 3 700
bicycles 2012 4 800
ham 2011 1 10
ham 2011 2 20
ham 2011 3 30
ham 2011 4 40
ham 2012 1 50
ham 2012 2 60
ham 2012 3 70
ham 2012 4 80
bicycles 2012 -3 100
bicycles 2012 -2 200
bicycles 2012 -1 300
bicycles 2012 0 400
bicycles 2013 -3 500
bicycles 2013 -2 600
bicycles 2013 -1 700
bicycles 2013 0 800
ham 2012 -3 10
ham 2012 -2 20
ham 2012 -1 30
ham 2012 0 40
ham 2013 -3 50
ham 2013 -2 60
ham 2013 -1 70
ham 2013 0 80
If we save that query as [SalesUnion] then we can use it to produce our totals like so
SELECT
Item,
FiscalYear,
Quarter,
TotalSales,
(
SELECT
SUM(su.TotalSales)
FROM SalesUnion su
WHERE su.Item = s.Item
AND su.FiscalYear = s.FiscalYear
AND (su.Quarter Between s.Quarter - 3 And s.Quarter)
) AS SalesLast12Months
FROM SalesSummary s
Or, if you don't want to rely on a saved query you can do it all in one go:
SELECT
Item,
FiscalYear,
Quarter,
TotalSales,
(
SELECT
SUM(su.TotalSales)
FROM
(
SELECT
Item,
FiscalYear,
Quarter,
TotalSales
FROM SalesSummary
UNION ALL
SELECT
Item,
FiscalYear + 1,
Quarter - 4,
TotalSales
FROM SalesSummary
) su
WHERE su.Item = s.Item
AND su.FiscalYear = s.FiscalYear
AND (su.Quarter Between s.Quarter - 3 And s.Quarter)
) AS SalesLast12Months
FROM SalesSummary s
Either way, the results are
Item FiscalYear Quarter TotalSales SalesLast12Months
-------- ---------- ------- ---------- -----------------
bicycles 2011 1 100 100
bicycles 2011 2 200 300
bicycles 2011 3 300 600
bicycles 2011 4 400 1000
bicycles 2012 1 500 1400
bicycles 2012 2 600 1800
bicycles 2012 3 700 2200
bicycles 2012 4 800 2600
ham 2011 1 10 10
ham 2011 2 20 30
ham 2011 3 30 60
ham 2011 4 40 100
ham 2012 1 50 140
ham 2012 2 60 180
ham 2012 3 70 220
ham 2012 4 80 260

Answer 2

The variable Formula should contain this:
SELECT (SUM(su.Net_Cash_Flow_Operating) - SUM(su.Capital_Expenditures)) FROM (SELECT Ticker, [Year], Period, Net_Cash_Flow_Operating, Capital_Expenditures FROM Cash_Flow_Statements UNION ALL SELECT Ticker, [Year] + 1, Period - 4, Net_Cash_Flow_Operating, Capital_Expenditures FROM Cash_Flow_Statements) su WHERE su.Ticker = c.Ticker AND su.[Year] = c.[Year] AND (su.Period Between c.Period - 3 And c.Period)