CREATE TABLE table_name_79 (date VARCHAR, location VARCHAR, result VARCHAR, competition VARCHAR)

What date has a result of win, in a friendly competition in Porto?
SELECT date FROM table_name_79 WHERE result = "win" AND competition = "friendly" AND location = "porto"
SELECT "date" FROM "table_name_79" WHERE "competition" = "friendly" AND "location" = "porto" AND "result" = "win"