For example I have 4 same type tables which contains:
1 table 1995 year's invoices
2 table 1996 year's invoices
3 table 1997 year's invoices
4 table 1998 year's invoices

And for example user wants to know some information from 96-97 years.
How connect those tables into one to have virtually one table, not 4?

Can I use views? Is there easiest way to do it?

Giedrius