query: SELECT classroom ,  count(DISTINCT grade) FROM list GROUP BY classroom
question: For each classroom, are showing classroom number and are counting number of distinct grades that what is using 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: For each classroom, are showing classroom number and are counting number of distinct grades that what is using room.