user: Question: How many opponents did they play on 17/05/2009?
Columns: ['Competition', 'Round', 'Opponent', 'Result', 'Score', 'Home/Away', 'Venue', 'Attendance', 'Date']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Super League XIV', '17 †', 'Wigan Warriors', 'Win', '6-12', 'Away', 'JJB Stadium', '14,377', '08/02/2009']
SQL:

assistant: SELECT COUNT("Opponent") FROM "Table" WHERE "Date" = '17/05/2009';