US Open ในปีใดที่มี Maikel Scheffers เป็นพันธมิตร?ไม่จำเป็นต้องใช้โต๊ะทั้งหมด
What year was the US Open that had a partnering of Maikel Scheffers?It is not neccessary to use all the tables.
 table_name_56:  (year [ INTEGER ] partnering [ VARCHAR ] championship [ VARCHAR) ]
SELECT SUM(year) FROM table_name_56 WHERE partnering = "maikel scheffers" AND championship = "us open"