what are the four most frequently prescribed drugs for patients in the same hospital encounter after having received a entral infus nutrit sub procedure in the last year?
select t3.drug from ( select t2.drug, dense_rank() over ( order by count(*) desc ) as c1 from ( select admissions.subject_id, procedures_icd.charttime, admissions.hadm_id from procedures_icd join admissions on procedures_icd.hadm_id = admissions.hadm_id where procedures_icd.icd9_code = ( select d_icd_procedures.icd9_code from d_icd_procedures where d_icd_procedures.short_title = 'entral infus nutrit sub' ) and datetime(procedures_icd.charttime,'start of year') = datetime(current_time,'start of year','-1 year') ) as t1 join ( select admissions.subject_id, prescriptions.drug, prescriptions.startdate, admissions.hadm_id from prescriptions join admissions on prescriptions.hadm_id = admissions.hadm_id where datetime(prescriptions.startdate,'start of year') = datetime(current_time,'start of year','-1 year') ) as t2 on t1.subject_id = t2.subject_id where t1.charttime < t2.startdate and t1.hadm_id = t2.hadm_id group by t2.drug ) as t3 where t3.c1 <= 4