user: Question: What is the total number of silver medals for karate athletes with over 2 golds?
Columns: ['Athlete', 'Sport', 'Asian Games', 'Gold', 'Silver', 'Bronze', 'Total']
Types: ['text', 'text', 'text', 'real', 'real', 'real', 'real']
Sample row: ['Mohammad Nassiri', 'Weightlifting', '1966–1974', 4.0, 1.0, 0.0, 5.0]
SQL:

assistant: SELECT SUM("Silver") FROM "Table" WHERE "Sport" = 'karate' AND "Gold" > 2.0;