query: SELECT document_id ,  count(DISTINCT employee_id) FROM Circulation_History GROUP BY document_id;
question: For each document, list the number of employee which that showed up in the circulation historys of that there document. List the document ids and number of employee.
query_toks: SELECT document_id , count ( DISTINCT employee_id ) FROM Circulation_History GROUP BY document_id ;
query_toks_no_value: select document_id , count ( distinct employee_id ) from circulation_history group by document_id
question_toks: For each document, list the number of employee which that showed up in the circulation historys of that there document. List the document ids and number of employee.