Join BCS lists

I have two tables in database: table1 and table2.

They have fields:

Table1.Id (primary key)

Table1.CategoryId

Table2.CategoryId (primary key)

Table2.CategoryName

How can i join this tables by using BCS lists (like table1 join table2 on table1.CategoryId=table2.CategoryId).

I need one list that will show: Id, CategoryId, CategoryName.