Ah ha! You have been eating something on your table, i.e. oranges or other things that might be sweet to draw the ants. To get rid of them.. you must clean up your mess completely after eating particularly sweet things.. spray with an ant spray(they are probably sugar ants).. the ants are getting in someplace.. i.e. corners of windows, doors, etc and one must make sure there is caulking around the windows to keep the pesky things out.