เมื่อเดือนที่แล้วผู้ป่วยหมายเลข 028-55503 ได้สั่งยาตัวแรกอะไร?ไม่จำเป็นต้องใช้ทุกตาราง
what was the first drug being prescribed for patient 028-55503 during the last month?It is not neccessary to use all the tables.
 treatment:  treatmentid [ number]  patientunitstayid [ number]  treatmentname [ text]  treatmenttime [ time] 
SELECT medication.drugname FROM medication WHERE medication.patientunitstayid IN (SELECT patient.patientunitstayid FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '028-55503')) AND DATETIME(medication.drugstarttime, 'start of month') = DATETIME(CURRENT_TIME(), 'start of month', '-1 month') ORDER BY medication.drugstarttime LIMIT 1