Calculate the average duration of absense of disabled male students.
average duration = DIVIDE(SUM(month), COUNT(month)); duration of absence refers to month; disabled male students refers to disabled.name who are IN male.name;
SELECT AVG(T1.month) FROM longest_absense_from_school AS T1 INNER JOIN disabled AS T2 ON T2.name = T1.name INNER JOIN male AS T3 ON T3.name = T2.name