set serveroutput on declare a ; b ; c number; begin c:=(a+b)/(a-b); dbms_output.put_line(c); exception when zero_divide then dbms_output.put_line('除数不许为零!'); end; / set serveroutput on declare var_ename emp.ename%type; --声明与ename列类型相同的变量 var_job emp.…