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

Question: List the date of each treatment, together with the first name of the professional who operated it.
SQL: SELECT T1.date_of_treatment, T2.first_name FROM Treatments AS T1 JOIN Professionals AS T2 ON T1.professional_id = T2.professional_id