A family of Microsoft relational database management systems designed for ease of use.
You could create a union query AllAccountNames that returns all account names:
SELECT [AccountName] FROM [QueryFor2011]
UNION
SELECT [AccountName] FROM [QueryFor2012]
Then create a new query like this:
SELECT [AllAccountNames].[AccountName], [QueryFor2011].[TotalAmount] AS Total2011, [QueryFor2012].[TotalAmount] AS Total2012
FROM [QueryFor2011] RIGHT JOIN ([AllAccountNames] LEFT JOIN [QueryFor2012] ON [AllAccountNames].[AccountName] = [QueryFor201].[AccountName]) ON [QueryFor2012].[AccountName] = [AllAccountNames].[AccountName]
Change the names to suit your situation.