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

Question: Which professionals have done at least two types of treatments? List the professional id and cell phone.
SQL: SELECT T1.professional_id, T1.cell_number FROM Professionals AS T1 JOIN Treatments AS T2 ON T1.professional_id = T2.professional_id GROUP BY T1.professional_id HAVING COUNT(*) >= 2