David E. Kelley เขียนซีซันใดในซีรีส์ 7 ?ไม่จำเป็นต้องใช้ตารางทั้งหมด
What seasons  in series 7 did David E. Kelley write ?It is not neccessary to use all the tables.
 table_23279434_1:  (season__number [ VARCHAR ] written_by [ VARCHAR ] series__number [ VARCHAR) ]
SELECT COUNT(season__number) FROM table_23279434_1 WHERE written_by = "David E. Kelley" AND series__number = 7