user: Question: What is Volume:Issue, when Artist is Elton John, and when Weeks on Top is 4?
Columns: ['Volume:Issue', 'Issue Date(s)', 'Weeks on Top', 'Song', 'Artist']
Types: ['text', 'text', 'real', 'text', 'text']
Sample row: ['18:21-23', '6 January - 20 January', 2.0, '" Clair "', "Gilbert O'Sullivan"]
SQL:

assistant: SELECT "Volume:Issue" FROM "Table" WHERE "Artist" = 'Elton John' AND "Weeks on Top" = 4.0;