Table schema:
CREATE TABLE Dogs (date_arrived VARCHAR, date_departed VARCHAR, dog_id VARCHAR); CREATE TABLE Treatments (dog_id VARCHAR)

Question: What are the arriving date and the departing date of the dogs who have gone through a treatment?
SQL: SELECT DISTINCT T1.date_arrived, T1.date_departed FROM Dogs AS T1 JOIN Treatments AS T2 ON T1.dog_id = T2.dog_id