Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_28138035_4 (womens_doubles VARCHAR, year_location VARCHAR)

### Question ###
Name the number of womens doubles for 2011 rio de janeiro

### Accurate SQL ###

SELECT COUNT(womens_doubles) FROM table_28138035_4 WHERE year_location = "2011 Rio de Janeiro"