I have created tables which are something like below

Table: airplane
reg_nbr md_name
1 Skylane
2 Skyhawk
3 Citation
4 Caravan

Table: service
service_nbr reg_nbr date_service
11 1 8-JUL-04
12 2 14-JUL-04
13 3 15-JUL-04
14 4 9-OCT-04
15 5 10-JUN-04

Table: maintain (person_nbr,service_nbr,reg_nbr are all primary keys)
person_nbr service_nbr reg_nbr
101 11 1
102 12 2
103 13 3
104 14 4
105 15 5

Table: employee
person_nbr last_name first_name
101 Chan A
102 Smith B
103 Jones c
104 Wilson D

I'm trying to find the number of airplanes service in JULY with the airplane reg_nbr, md_name, date_service and employee last and first name listed... this seems to be very complicated..
Am i suppose to join them all together??
I'm not sure how I am suppose to group them Thank you!

homework!!

what have you tried? what do you think is required?

do you know what a join is? could you explain it briefly?