นับจำนวนผู้ป่วยที่ได้รับการล้างสายยางในกระเพาะอาหารไปแล้ว 2 ครั้ง ในปี 2102 ไม่จำเป็นต้องใช้ทุกตาราง
count the number of patients who have already received the gastric tube irrigat nec two times in 2102.It is not neccessary to use all the tables.
 prescriptions:  row_id [ number]  subject_id [ number]  hadm_id [ number]  startdate [ time]  enddate [ time]  drug [ text]  dose_val_rx [ text]  dose_unit_rx [ text]  route [ text] 
SELECT COUNT(DISTINCT t1.subject_id) FROM (SELECT admissions.subject_id, COUNT(*) AS c1 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 = 'gastric tube irrigat nec') AND STRFTIME('%y', procedures_icd.charttime) = '2102' GROUP BY admissions.subject_id) AS t1 WHERE t1.c1 = 2