What is the percentage difference between month 0 absence and month 9 absence?
percentage difference = CONCAT(DIVIDE(MULTIPLY(SUBTRACT(COUNT(name WHERE month = 0), COUNT(name WHERE month = 9)), 100), COUNT(name WHERE month = 0)),'%');
SELECT CAST(((SUM(IIF(month = 0, 1, 0)) - SUM(IIF(month = 9, 1, 0)))) AS REAL) * 100 / SUM(IIF(month = 0, 1, 0)) FROM longest_absense_from_school