Does it really matter if he's on the table? I personally let my cats go on the table (it loses it's appeal after a while if they never find anything interesting on it), but if you're dead set against it, then you have to make it an undesirable place to go. Put sticky tape or aluminum pie plates or tinfoil on it while you aren't using it, or get something called Sscat, which is a motion-detecting device that emits a blast of canned air when anyone goes in it's range. Also make sure you cat has other high places he can go instead. Cats love to be up off the ground, so if his only option is the table, he's going to keep going up there. Get a tall cat condo or a space on a bookshelf for him, or some window perches.
"To close your eyes will not ease another's pain." ~ Chinese Proverb
“We must not refuse to see with our eyes what they must endure with their bodies.” ~ Gretchen Wyler