นับจำนวนผู้ตรวจพบปอดฟกช้ำเปิดแล้วไม่ได้กลับมาโรงพยาบาลภายใน 2 เดือน ไม่จำเป็นต้องใช้โต๊ะทั้งหมด
count the number of people who were diagnosed with lung contusion-open and didn't come back to the hospital within 2 months.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 (SELECT COUNT(DISTINCT t1.subject_id) FROM (SELECT admissions.subject_id, diagnoses_icd.charttime FROM diagnoses_icd JOIN admissions ON diagnoses_icd.hadm_id = admissions.hadm_id WHERE diagnoses_icd.icd9_code = (SELECT d_icd_diagnoses.icd9_code FROM d_icd_diagnoses WHERE d_icd_diagnoses.short_title = 'lung contusion-open')) AS t1) - (SELECT COUNT(DISTINCT t2.subject_id) FROM (SELECT admissions.subject_id, diagnoses_icd.charttime FROM diagnoses_icd JOIN admissions ON diagnoses_icd.hadm_id = admissions.hadm_id WHERE diagnoses_icd.icd9_code = (SELECT d_icd_diagnoses.icd9_code FROM d_icd_diagnoses WHERE d_icd_diagnoses.short_title = 'lung contusion-open')) AS t2 JOIN admissions ON t2.subject_id = admissions.subject_id WHERE t2.charttime < admissions.admittime AND DATETIME(admissions.admittime) BETWEEN DATETIME(t2.charttime) AND DATETIME(t2.charttime, '+2 month'))