database in access

I need a simple database with some pre definied queries. See attached excel file for example of data. The basic idea: - there will be a main table with about 8 columns - every week I need to import a new table (same structure as the main table) and compare it with data in the main table. If the record from the new table allready exists in the main table then nothing sould happen. If the record doesn't exist then it should be added to the main table. Third option is that a record from the main table does not exist in the new table anymore. Then the record in the main table should be updated stating that the record is no more present and the date from new table should be indicated in column 9 of the main table. The queries should do the following: - select records from the main table based on criteria for code1 and calculate average code3 for those records. - select records from the main table based on criteria for code1 + code2 and calculate average code3 for those records. - calculate average number of days between indicated date and date in field 8 for all records or records specified by code3 criteria ## Deliverables Have a look at the excel file in the attachment. Sheet 'main' would serve for the table 'main' and sheet 'new' represents how the weekly new file would look like.