ระบุจำนวนคนไข้ที่มีประกัน Medicare และโรคหลักคือ Acidosis?ไม่จำเป็นต้องใช้ตารางทั้งหมด
provide the number of patients whose insurance is medicare and primary disease is acidosis?It is not neccessary to use all the tables.
 prescriptions:  subject_id [ text]  hadm_id [ text]  icustay_id [ text]  drug_type [ text]  drug [ text]  formulary_drug_cd [ text]  route [ text]  drug_dose [ text] 
SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic WHERE demographic.insurance = "Medicare" AND demographic.diagnosis = "ACIDOSIS"