instruction: tell me the top three most common drugs prescribed for patients aged 30s until 2 years ago?
response: SELECT t1.drugname FROM (SELECT medication.drugname, DENSE_RANK() OVER (ORDER BY COUNT(*) DESC) AS c1 FROM medication WHERE medication.patientunitstayid IN (SELECT patient.patientunitstayid FROM patient WHERE patient.age BETWEEN 30 AND 39) AND DATETIME(medication.drugstarttime) <= DATETIME(CURRENT_TIME(), '-2 year') GROUP BY medication.drugname) AS t1 WHERE t1.c1 <= 3