Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_21378160_2 (opponent VARCHAR, date VARCHAR)
### Question:
How many opponents did they play on 17/05/2009?
### Answer:
SELECT COUNT(opponent) FROM table_21378160_2 WHERE date = "17/05/2009"