Question: What year was the No. 7 charts?
SQL: SELECT AVG("Year") FROM "2-12937449-4" WHERE "Charts" = 'No. 7';

Question: What is the chart number of the Requebra album with sales smaller than 32000?
SQL: SELECT "Charts" FROM "2-12937449-4" WHERE "Sales" < 32000.0 AND "Álbum" = 'Requebra';