Access 2010 Crosstab Query Expression--in One Query - sql

Question

I would like to add this expression:
([2013]/[2012]-1) AS [Change%]
As a field to the crosstab query below:
TRANSFORM
Sum(Data.Spending)
SELECT
Data.Category
FROM
Data
WHERE
(((Data.Year)="2012" Or (Data.Year)="2013"))
GROUP BY
Data.Category
PIVOT
Data.Year;
This is solved through using another table in this thread: Access 2007 Crosstab Query Expression
But for my purposes I need to have everything together in one query.
This is because I am writing SQL in another program, http://www.ljzsoft.com/ppt-report.htm, which uses the query to directly access an Access database.

Answer 1

As you have probably discovered, Access won't let us use a Crosstab query as a subquery. If we try to do
SELECT ...
FROM
(
TRANSFORM
we get "Syntax error in FROM clause". One workaround is to do all of the aggregations, create the derived (calculated) values, UNION them together, and then "crosstab" that. In your case:
TRANSFORM Sum(ColValue) AS SumOfColValue
SELECT Category
FROM
(
SELECT Category, [Year] AS ColHead, Sum(Spending) AS ColValue
FROM Data
WHERE [Year] IN ("2012", "2013")
GROUP BY Category, [Year]
UNION ALL
SELECT
curr.Category,
"Change%" AS ColHead,
(curr.SumOfSpending/prev.SumOfSpending-1) AS ColValue
FROM
(
SELECT Category, [Year], Sum(Spending) AS SumOfSpending
FROM Data
WHERE [Year] IN ("2012", "2013")
GROUP BY Category, [Year]
) AS curr
INNER JOIN
(
SELECT Category, [Year], Sum(Spending) AS SumOfSpending
FROM Data
WHERE [Year] IN ("2012", "2013")
GROUP BY Category, [Year]
) AS prev
ON prev.Category = curr.Category
AND CLng(prev.[Year]) = (CLng(curr.[Year]) - 1)
)
GROUP BY Category
PIVOT ColHead
which, for my sample data, returns
Category 2012 2013 Change%
--------- ---- ---- -----------------
Category1 123 345 1.80487804878049
Category2 234 456 0.948717948717949
If that is too nasty for your liking then you might want to investigate whether your reporting tool supports calculated report fields (e.g., in Crystal Reports I believe they are called "Formula Fields").