ค้นหาจำนวนผู้ป่วยที่ออกจากโรงพยาบาลได้ในปี 2100 ไม่จำเป็นต้องใช้โต๊ะทั้งหมด
find out how many patients were discharged from the hospital in 2100.It is not neccessary to use all the tables.
 labevents:  row_id [ number]  subject_id [ number]  hadm_id [ number]  itemid [ number]  charttime [ time]  valuenum [ number]  valueuom [ text] 
SELECT COUNT(DISTINCT admissions.subject_id) FROM admissions WHERE NOT admissions.dischtime IS NULL AND STRFTIME('%y', admissions.dischtime) = '2100'