Question: is the riddler and the joker the same character

Answer: No, The fallout from the Riddler's failed scheme is played out in Batman: Gotham Knights #50-53. In the story ``Pushback'', Hush reappears and beats Riddler senseless across a rooftop. Seeking refuge, Riddler goes to the Joker and the Penguin. He offers to tell the Joker who had killed his pregnant wife Jeannie if the Clown Prince of Crime would protect him from Hush. Joker immediately agrees, but eventually Hush, with the help of the impostor Prometheus, defeats him, forcing Riddler to flee for his life.