例外是在错误的地方吗?放在哪里最好?

LOOP BEGIN-EXCEPTION-END

END BEGIN-EXCEPTION- 结束

create or replace Procedure EY IS
  CURSOR c1 is 
    select ey_id , cycle_id
    from mvs v
    cross join cycle s
  l_var c1%ROWTYPE;
BEGIN
  OPEN c1;
  LOOP
    BEGIN
      FETCH c1 into l_var;
      EXIT when c1%NOTFOUND;
      insert into EY (EY_id, cycle_id, create_dt, create_user_id)
        values (l_var.ey_id, l_var.cycle_id, trunc(sysdate), '1');
    EXCEPTION
      WHEN DUP_VAL_ON_INDEX THEN
      DBMS_OUTPUT.PUT_LINE('duplicate value');  
    end;                   --> you're missing this END
  END LOOP;
  close c1;
END EY;

如果您正确地缩进代码,就更容易发现罪魁祸首。