user: Question: What is Opponent, when Date is 8 April 1999?
Columns: ['Date', 'Round', 'Opponent', 'Venue', 'Result', 'Attendance']
Types: ['text', 'text', 'text', 'text', 'text', 'real']
Sample row: ['17 September 1998', 'R1', 'Helsingborg', 'H', '1-0', 17714.0]
SQL:

assistant: SELECT "Opponent" FROM "Table" WHERE "Date" = '8 April 1999';