user: Question: On how many different dates was a game against Houston played?
Columns: ['Game', 'Date', 'Opponent', 'Score', 'High points', 'High rebounds', 'High assists', 'Location', 'Record']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [2.0, 'June 1', 'Charlotte', 'W 82-79', 'Sales (24)', 'McWilliams (9)', 'S. Johnson (7)', 'TD Waterhouse Centre', '1-1']
SQL:

assistant: SELECT COUNT("Date") FROM "Table" WHERE "Opponent" = 'Houston';