instruction: how many patients with drug type base were diagnosed with diaphragmatic hernia?
response: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN diagnoses ON demographic.hadm_id = diagnoses.hadm_id INNER JOIN prescriptions ON demographic.hadm_id = prescriptions.hadm_id WHERE diagnoses.short_title = "Diaphragmatic hernia" AND prescriptions.drug_type = "BASE"