instruction: what are the four most frequent drug that were prescribed during the same month to the colon ca male patients aged 50s after they had been diagnosed with colon ca, in this year?
response: SELECT t3.drugname FROM (SELECT t2.drugname, DENSE_RANK() OVER (ORDER BY COUNT(*) DESC) AS c1 FROM (SELECT patient.uniquepid, diagnosis.diagnosistime FROM diagnosis JOIN patient ON diagnosis.patientunitstayid = patient.patientunitstayid WHERE diagnosis.diagnosisname = 'colon ca' AND DATETIME(diagnosis.diagnosistime, 'start of year') = DATETIME(CURRENT_TIME(), 'start of year', '-0 year')) AS t1 JOIN (SELECT patient.uniquepid, medication.drugname, medication.drugstarttime FROM medication JOIN patient ON medication.patientunitstayid = patient.patientunitstayid WHERE patient.gender = 'male' AND patient.age BETWEEN 50 AND 59 AND DATETIME(medication.drugstarttime, 'start of year') = DATETIME(CURRENT_TIME(), 'start of year', '-0 year')) AS t2 ON t1.uniquepid = t2.uniquepid WHERE t1.diagnosistime < t2.drugstarttime AND DATETIME(t1.diagnosistime, 'start of month') = DATETIME(t2.drugstarttime, 'start of month') GROUP BY t2.drugname) AS t3 WHERE t3.c1 <= 4