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_name_79 (date VARCHAR, location VARCHAR, result VARCHAR, competition VARCHAR)
### Question:
What date has a result of win, in a friendly competition in Porto?
### Answer:
SELECT date FROM table_name_79 WHERE result = "win" AND competition = "friendly" AND location = "porto"