user: ### NOW ANSWER:
Question: What was the attendance on 31 January 2009 when the opponent was Airdrie United?
Columns: ['Date', 'Opponent', 'Venue', 'Result', 'Attendance']
Types: ['text', 'text', 'text', 'text', 'real']
Sample row: ['2 August 2008', 'Dunfermline Athletic', 'Firhill', '1-0', 3092.0]
SQL:

assistant: SELECT AVG("Attendance") FROM "Table" WHERE "Opponent" = 'Airdrie United' AND "Date" = '31 January 2009';