What percentage of matches played on 2005/07/30 belong to the F1 division?
Division refers to Div; DIVIDE(COUNT(Div = 'F1', Date = '2005/07/30'), COUNT(Div, Date = '2005/07/30')) as percentage;
SELECT CAST(SUM(CASE WHEN Div = 'F1' THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(Div) FROM matchs WHERE Date = '2005-07-30' 