CREATE TABLE table_28138035_20 (year_location VARCHAR, mens_doubles VARCHAR)

How many years did lin gaoyuan wu jiaji play mens doubles?
SELECT COUNT(year_location) FROM table_28138035_20 WHERE mens_doubles = "Lin Gaoyuan Wu Jiaji"
SELECT COUNT("year_location") FROM "table_28138035_20" WHERE "Lin Gaoyuan Wu Jiaji" = "mens_doubles"