Creating a summary table from accounting transactions

I have an accounting transactions table that contains the following fields:

Company - two digits numeric

Cost Centre - four digits numeric

Account code - 5 digits numeric

Account Type - 1 digit numeric (first digit of account code)

Account Group Ten - 5 digit numeric (first four digits of account code with a 0 appended)

Year - YYYY

Month - MM

Year / month - YYYYMM

Amount

I need to create two separate tables by Company, Cost Centre and Account Code with column headings Year / Month.  

The first table (a profit and loss table) has to be just those transactions with an Account Code between 00000 to 39999 and should contain the totals of Amount for each Year / Month.

The second table (a balance sheet table) has to be just those transactions with an Account Code between 60000 to 99999 and should contain accumulated totals of Amount to date by Year Month (accumulated from the very beginning, not by year)

Any help geatly appreciated.