การทดสอบเมทฮีโมโกลบินในห้องปฏิบัติการมีค่าใช้จ่ายเท่าไร?ไม่จำเป็นต้องใช้ตารางทั้งหมด
how much cost is it to perform methemoglobin lab tests?It is not neccessary to use all the tables.
 transfers:  row_id [ number]  subject_id [ number]  hadm_id [ number]  icustay_id [ number]  eventtype [ text]  careunit [ text]  wardid [ number]  intime [ time]  outtime [ time] 
SELECT DISTINCT cost.cost FROM cost WHERE cost.event_type = 'labevents' AND cost.event_id IN (SELECT labevents.row_id FROM labevents WHERE labevents.itemid IN (SELECT d_labitems.itemid FROM d_labitems WHERE d_labitems.label = 'methemoglobin'))