มีการใช้พื้นผิวดินมากกว่าพื้นผิวแข็งหรือไม่ ไม่จำเป็นต้องใช้โต๊ะทั้งหมด
was there more clay surfaces used than hard surfaces ?It is not neccessary to use all the tables.
 table_204_47:  id [ number]  "outcome" [ text]  "no." [ number]  "date" [ text]  "tournament" [ text]  "surface" [ text]  "partner" [ text]  "opponents" [ text]  "score" [ text] 
SELECT (SELECT COUNT(*) FROM table_204_47 WHERE "surface" = 'clay') > (SELECT COUNT(*) FROM table_204_47 WHERE "surface" = 'hard')