user: ### NOW ANSWER:
Question: When has an Opponent of at Seattle Mariners?
Columns: ['Date', 'Opponent', 'Score', 'Loss', 'Save']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['June 1', 'at Seattle Mariners', '4-1', 'Thompson', 'Ayala']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Opponent" = 'at Seattle Mariners';