seaching for info between dates in a table

Basically I have two groups of data



Group 1 is machine info and has



Serial Number Build Month Commission Month





Group 2 is warranty info and has



Serial Number Service Claim Value of Service Claim



What I need to do is for all machines built in a given month count the number of claims within a given number of months after commissioning and the total value of the claims.





Eg



If I have a machine serial number abc123 built in jan 07 and commissioned mar 07 I need to search the table of data in group 2 for the number of claims between mar 07 and may 07 and also the total value of those claims



If you have any suggestions it would be a great help.



Thanks

Colin