What is the ratio of students who have payment due and those who do not have payment due?
ratio =  DIVIDE(COUNT(name WHERE `bool` = 'pos'), COUNT(name WHERE `bool` = 'neg')); have payment due refers to `bool` = 'pos'; no payment due refers to `bool` = 'neg';
SELECT CAST(SUM(IIF(`bool` = 'pos', 1, 0)) AS REAL) / SUM(IIF(`bool` = 'neg', 1, 0)) FROM no_payment_due