query: SELECT last_name FROM Teachers EXCEPT SELECT T1.last_name FROM Teachers AS T1 JOIN Detention AS T2 ON T1.teacher_id  =  T2.teacher_id
question: Finding a names last alla teacher what ain't a-involved any a detention.
query_toks: SELECT last_name FROM Teachers EXCEPT SELECT T1.last_name FROM Teachers AS T1 JOIN Detention AS T2 ON T1.teacher_id = T2.teacher_id
query_toks_no_value: select last_name from teachers except select t1 . last_name from teachers as t1 join detention as t2 on t1 . teacher_id = t2 . teacher_id
question_toks: Finding a names last alla teacher what ain't a-involved any a detention.