user: Question: What is the average Silver, when Gold is less than 0?
Columns: ['Rank', 'Nation', 'Gold', 'Silver', 'Bronze', 'Total']
Types: ['text', 'text', 'real', 'real', 'real', 'real']
Sample row: ['1', 'Norway', 15.0, 10.0, 1.0, 26.0]
SQL:

assistant: SELECT AVG("Silver") FROM "Table" WHERE "Gold" < 0.0;