Hello Subash,
Without a sample fo your data, it is extremely hard to decide what sort of approach would most likely work for you.
Is it possible for you to upload a cutdown (maybe 100 rows per sheet) and sanitised (sensitive data changed) version of your spreadsheet together with an indication of the resultant output that you require?
From what you have said, I am guessing that you would want to find unique MailId and extract relevant matching company information to a new sheet without concern for the product and other details.
You refer to the file as a database and, if it is properly set up, it might be possible to use SQL to extract the data that you want. Otherwise it will likely require a search and extract VBA code module. Unless, of course you have a complete list of the unique MailId values which might allow a formulaic approach.
So, ultimately, we need to have a much better idea of what you have and exactly what you want as an end result.
Regards
Harry