Database: dog_kennels
Question: What are the id, the role, and the first name of the professionals who have performed two or more treatments?
SQL: select t1.professional_id ,  t1.role_code ,  t1.first_name from professionals as t1 join treatments as t2 on t1.professional_id  =  t2.professional_id group by t1.professional_id having count(*)  >=  2