Table schema:
CREATE TABLE Professionals (professional_id VARCHAR, role_code VARCHAR, first_name VARCHAR); CREATE TABLE Treatments (professional_id VARCHAR)

Question: Which professionals have done at least two treatments? List the professional's id, role, and first name.
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