user: Question: What is the sum of Weeks on Top for the Volume:Issue 34:9-12?
Columns: ['Volume:Issue', 'Issue Date(s)', 'Weeks on Top', 'Song', 'Artist']
Types: ['text', 'text', 'real', 'text', 'text']
Sample row: ['34:6-8', '20 December 1980 – 31 January 1981', 7.0, '" (Just Like) Starting Over "', 'John Lennon']
SQL:

assistant: SELECT SUM("Weeks on Top") FROM "Table" WHERE "Volume:Issue" = '34:9-12';