Table: football_match_data_4
Columns: date
opponent
venue
result
attendance

Question: Which Date has an Opponent of newcastle united, and a Result of 2–1?
SQL: SELECT "date" FROM football_match_data_4 WHERE "opponent" = 'newcastle united' AND "result" = '2–1'

Question: Which Date has an Opponent of manchester united, and a Venue A?
SQL: SELECT "date" FROM football_match_data_4 WHERE "opponent" = 'manchester united' AND "venue" = 'a'