query: SELECT classroom ,  count(DISTINCT grade) FROM list GROUP BY classroom
question: Each classroom, do show the classroom number and count em number distinct grade them uses em room.
query_toks: SELECT classroom , count ( DISTINCT grade ) FROM list GROUP BY classroom
query_toks_no_value: select classroom , count ( distinct grade ) from list group by classroom
question_toks: Each classroom, do show the classroom number and count em number distinct grade them uses em room.