Even the novels by authors who are most closely associated with stream-of-consciousness -- such as James Joyce, Virginia Woolf, and WIlliam Faulkner -- often only show stream-of-consciousness in sectons of the novels. Reading an entire novel written in stream-of-consciousness is possible, of course, but it would probably also be painful.
Different writers use stream-of-consciousness differently, but the tendency is to seek to disrupt the traditional structure of narrative. Some writers do without standard punctuation and sentence structure, for example. Other writers seek to place images and sensations side-by-side, so that they're experienced immediately rather than filtered through the unifying voice of a narrator. Here's an example of the latter from the opening to James Joyce's novel A Portrait of the Artist as a Young Man:
Once upon a time and a very good time it was there was a moocow coming
down along the road and this moocow that was coming down along the road
met a nicens little boy named baby tuckoo...
His father told him that story: his father looked at him through a
glass: he had a hairy face.
He was baby tuckoo. The moocow came down the road where Betty Byrne
lived: she sold lemon platt.
William Faulkner's The Sound and The Fury is an example of stream of consciousness narration