user: Question: How many points numbers had a class of 250cc, a year prior to 1978, yamaha as a team, and where wins was more than 0?
Columns: ['Year', 'Class', 'Team', 'Points', 'Wins']
Types: ['real', 'text', 'text', 'real', 'real']
Sample row: [1973.0, '500cc', 'Yamaha', 3.0, 0.0]
SQL:

assistant: SELECT COUNT("Points") FROM "Table" WHERE "Class" = '250cc' AND "Year" < 1978.0 AND "Team" = 'yamaha' AND "Wins" > 0.0;