For each classroom, show the classroom number and find how many students are using it.
SELECT classroom ,  count(*) FROM list GROUP BY classroom
SELECT classroom ,  count(*) FROM list GROUP BY classroom
[{'Classroom': 101, 'count(*)': 3}, {'Classroom': 102, 'count(*)': 7}, {'Classroom': 103, 'count(*)': 5}, {'Classroom': 104, 'count(*)': 4}, {'Classroom': 105, 'count(*)': 5}, {'Classroom': 106, 'count(*)': 7}, {'Classroom': 107, 'count(*)': 6}, {'Classroom': 108, 'count(*)': 2}, {'Classroom': 109, 'count(*)': 8}, {'Classroom': 110, 'count(*)': 6}, {'Classroom': 111, 'count(*)': 4}, {'Classroom': 112, 'count(*)': 3}]