query: SELECT Allergy ,  count(*) FROM Has_allergy GROUP BY Allergy
question: It is each different allergy that how many students do have?
query_toks: SELECT Allergy , count ( * ) FROM Has_allergy GROUP BY Allergy
query_toks_no_value: select allergy , count ( * ) from has_allergy group by allergy
question_toks: It is each different allergy that how many students do have?