[student] How to correct this error?

ORA-00937: not a single-group group function

I'm not entirely sure what this means, here is my script for diagnosis:

SELECT FH.HIRE_PRICE,

       SUM(S.CONC_SEATS_SOLD) * S.CONC_PRICE CONC_TAKINGS,
       SUM(S.ORD_SEATS_SOLD) * S.ORD_PRICE ORD_TAKINGS,
       SUM(S.CONC_SEATS_SOLD) * S.CONC_PRICE
     + SUM(S.ORD_SEATS_SOLD) * S.ORD_PRICE TOT_TAKINGS

                    FROM FILM
                    WHERE FILM_NAME = '&&F_NAME') AND
      S.FILM_NO =  (SELECT FILM_NO 
                    FROM FILM
                    WHERE FILM_NAME = '&&F_NAME') AND
      FH.CINEMA_CODE = (SELECT CINEMA_CODE
                        FROM CINEMA
                        WHERE CINEMA_NAME = '&&C_NAME') AND
      S.CINEMA_CODE =  (SELECT CINEMA_CODE
                        FROM CINEMA
                        WHERE CINEMA_NAME = '&&C_NAME') AND
      S.HIRE_START = FH.HIRE_START;

Your help awaited with glorious ecstasy :)
--

On the smeeter.
MHM 22x9
--
Received on Mon Oct 26 1998 - 07:16:34 CST