help in sql query

the relations are

MEMBERSHIP(membership_number (pk), cover_type(pk), start_date(pk), end_date)
PERSON(person_number(pk), surname, initials, street_address, suburb, , membership_number)
DOCTOR(doctor_number(pk), surname, initials, street_address, suburb)
PROVIDED-SERVICE(person_number(pk), doctor_number(pk), service_date(pk), service_number)
REBATE(service_number(pk), cover_type(pk), refund)
SERVICE(service_number(pk), service_name, service_description)


i am struggling in this query can any one help me

1)List the service-names and maximum refund payable for those services which have been provided to every person who has visited a doctor.

this query asks for info about those services provided to every person who has visited a doctor. For each such services, list the name of the service and the maximum refund for that service (i.e. the same service can have many different refunds, only list the highest refund). Maximum refund therefore refers to the maximum for each such service, not a maximum across all services.


2)what is the name and address of the doctor, or doctors, who have provided services to the smallest non-zero number of individual patients (regardless of the number of services they provided to each patient)?



i dont the answers for these queries if anyone help me in this regard i would be so thankful