For each classroom, report the classroom number and the number of grades using it.
SELECT classroom ,  count(DISTINCT grade) FROM list GROUP BY classroom
SELECT classroom ,  count(DISTINCT grade) FROM list GROUP BY classroom
[{'Classroom': 101, 'count(DISTINCT grade)': 1}, {'Classroom': 102, 'count(DISTINCT grade)': 1}, {'Classroom': 103, 'count(DISTINCT grade)': 1}, {'Classroom': 104, 'count(DISTINCT grade)': 1}, {'Classroom': 105, 'count(DISTINCT grade)': 1}, {'Classroom': 106, 'count(DISTINCT grade)': 1}, {'Classroom': 107, 'count(DISTINCT grade)': 1}, {'Classroom': 108, 'count(DISTINCT grade)': 1}, {'Classroom': 109, 'count(DISTINCT grade)': 1}, {'Classroom': 110, 'count(DISTINCT grade)': 1}, {'Classroom': 111, 'count(DISTINCT grade)': 1}, {'Classroom': 112, 'count(DISTINCT grade)': 1}]