Substracting values in excel from values in database

[freak11]

Hi guys,
I have got a large database with several million rows on microsoft access (or several small excel files serving as database) which I cannot run on excel due to size restrictions. The large database has two columns called time and volume.

I need a vba code or any other method for excel that compares the data in the attachment to the data in the large database. The comparison should be done in such a manner that volume C1 at 00:00 in the excel file Attachment 324133
is substracted from every value at 00:00 in the databaseAttachment 324138, volume C2 at 00:01 in the excel file from every value at 00:01 in the database, and so on up to 00:59


any ideas?