มีกี่ฤดูกาลที่มีคะแนนรวม N/A?ไม่จำเป็นต้องใช้ตารางทั้งหมด
How many seasons have points totals of N/A?It is not neccessary to use all the tables.
 table_28446:  "Season" [ real]  "Series" [ text]  "Team" [ text]  "Races" [ real]  "Wins" [ real]  "Poles" [ real]  "F/Laps" [ real]  "Podiums" [ real]  "Points" [ text]  "Position" [ text] 
SELECT COUNT("Season") FROM table_28446 WHERE "Points" = 'N/A'