นับจำนวนยาที่สั่งจ่ายตั้งแต่ 03/2105 ถึงผู้ป่วย 002-27661 ไม่จำเป็นต้องใช้ทุกตาราง
count the number of drugs that have been prescribed since 03/2105 to patient 002-27661.It is not neccessary to use all the tables.
 diagnosis:  diagnosisid [ number]  patientunitstayid [ number]  diagnosisname [ text]  diagnosistime [ time]  icd9code [ text] 
SELECT COUNT(*) FROM medication WHERE medication.patientunitstayid IN (SELECT patient.patientunitstayid FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '002-27661')) AND STRFTIME('%y-%m', medication.drugstarttime) >= '2105-03'