จำนวนผู้โดยสารทั้งหมดเป็นเท่าใด ?ไม่จำเป็นต้องใช้ทุกโต๊ะ
what is the total number of rider ?It is not neccessary to use all the tables.
 table_204_352:  id [ number]  "pos" [ text]  "no" [ number]  "rider" [ text]  "manufacturer" [ text]  "laps" [ number]  "time" [ text]  "grid" [ number]  "points" [ number] 
SELECT COUNT("rider") FROM table_204_352