instruction: list the top four most common drugs that patients were prescribed with in the same hospital visit after they were prescribed with ns 0.9% since 2102.
response: SELECT t3.drugname FROM (SELECT t2.drugname, DENSE_RANK() OVER (ORDER BY COUNT(*) DESC) AS c1 FROM (SELECT patient.uniquepid, medication.drugstarttime, patient.patienthealthsystemstayid FROM medication JOIN patient ON medication.patientunitstayid = patient.patientunitstayid WHERE medication.drugname = 'ns 0.9%' AND STRFTIME('%y', medication.drugstarttime) >= '2102') AS t1 JOIN (SELECT patient.uniquepid, medication.drugname, medication.drugstarttime, patient.patienthealthsystemstayid FROM medication JOIN patient ON medication.patientunitstayid = patient.patientunitstayid WHERE STRFTIME('%y', medication.drugstarttime) >= '2102') AS t2 ON t1.uniquepid = t2.uniquepid WHERE t1.drugstarttime < t2.drugstarttime AND t1.patienthealthsystemstayid = t2.patienthealthsystemstayid GROUP BY t2.drugname) AS t3 WHERE t3.c1 <= 4