Actually this is good question. And this can deserve also some images.
I don't have exactly gaming table, but.
My table with size 160x90, which is made from one piece. Under this main part is hidden two extendable parts on the both end and table is possible to enlarge to 210x90 up to 260x90. The main advantage os this table is, that you don't need to remove anything from table, because the moving parts can be moved anytime you want and you need.
This table is very good for playing Carcassonne, the only table border is it's heigh (90 cm). But when game reach one of the ends it can be enlarged and added extra 50cm for placing tiles (which means 11 columns of Carcassonne tiles
Sorry no picture, I have it on cabin, where we used to play games.