ใครเล่นบนพื้นแข็ง?ไม่จำเป็นต้องใช้โต๊ะทั้งหมด
Who played on a hard surface?It is not neccessary to use all the tables.
 table_name_14:  (partner [ VARCHAR ] surface [ VARCHAR) ]
SELECT partner FROM table_name_14 WHERE surface = "hard"