What are all the service types?
select * from ref_service_types
For each of them, what is the description, code and the corresponding count of service?
select t1.service_type_description, t2.service_type_code, count(*) from ref_service_types as t1 join services as t2 on t1.service_type_code = t2.service_type_code group by t2.service_type_code