ผู้ป่วยที่ต้องนอนโรงพยาบาลเกิน 29 วัน มีปริมาณยาไม่มากเท่าไร ไม่จำเป็นต้องใช้ทุกโต๊ะ
how many patients who stayed in hospital for more than 29 days had nu roue of drug administration?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 INNER JOIN prescriptions ON demographic.hadm_id = prescriptions.hadm_id WHERE demographic.days_stay > "29" AND prescriptions.route = "NU"