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_name_79 ( date VARCHAR, location VARCHAR, result VARCHAR, competition VARCHAR )

### Question ###
What date has a result of win, in a friendly competition in Porto?

### Accurate SQL ###

SELECT date FROM table_name_79 WHERE result = "win" AND competition = "friendly" AND location = "porto"