user: Question: What Surface has a Date of 15 February 1988?
Columns: ['Outcome', 'Date', 'Championship', 'Surface', 'Opponent in the final', 'Score in the final']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Runner-up', '26 May 1986', 'French Open, Paris, France', 'Clay', 'Ivan Lendl', '3–6, 2–6, 4–6']
SQL:

assistant: SELECT "Surface" FROM "Table" WHERE "Date" = '15 February 1988';