select e1.dept_name,count(student_id)as student_number from Department as e1 left join Student as e2 on e1.dept_id=e2.dept_id group by dept_name order by student_number desc,dept_name asc ...

dbms_system.set_sql_trace_in_session相当于设置了level的。 综上：sql_trace已经被废弃，可以由10046来代替。 为了使跟踪更加灵活，oracle ...

Determines how Oracle handles the SQL statement. The following options are recognized: V6 (or 0) specifies version 6 behavior. NATIVE (or 1) specifies normal behavior for the database to which the ...