น้ำหนักรวมของรุ่นบิ๊กบอยและรุ่น m1 คือเท่าไร ?ไม่จำเป็นต้องใช้โต๊ะทั้งหมดครับ
what is the combined weight of the big boy and the m1 ?It is not neccessary to use all the tables.
 table_204_850:  id [ number]  "name" [ text]  "railway" [ text]  "series" [ text]  "maker" [ text]  "dates" [ text]  "drive" [ text]  "weight" [ text]  "power" [ text]  "notes" [ text] 
SELECT SUM("weight") FROM table_204_850 WHERE "name" IN ('big boy', 'm1')