CREATE TABLE table_28138035_4 (womens_doubles VARCHAR, year_location VARCHAR)

Name the number of womens doubles for 2011 rio de janeiro
SELECT COUNT(womens_doubles) FROM table_28138035_4 WHERE year_location = "2011 Rio de Janeiro"
SELECT COUNT("womens_doubles") FROM "table_28138035_4" WHERE "2011 Rio de Janeiro" = "year_location"