해석해보기

select employee_id

from employees

where employee_id in (select manager_id

   from employees);

select employee_id

from employees

where exists (select 'x'

   from employees m

   where e.manager_id = m.employee_id);

select distinct m.employee_id

from employees e 

join employees m

on e.manager_id = m.employees_id;

select last_name from employees

where employee_id not in

                         (select manager_id

                        from employees

                        where manager_id is not null);

=---------------------------------------------------------=

DECLARE

 TYPE t_rec is record

        (v_sal number(8),

        v_minsal number(8) default 1000,

        v_hire_date employees.hire_date%type,

        v_rec1 employees%rowtype);

 v_myrec t_rec;

BEGIN

 v_myrec.v_sal := v_myrec.v_minsal + 500;

 v_myrec.v_hire_date := sysdate;

 SELECT * INTO v_myrec.v_rec1

 FROM employees

 WHERE employee_id = 100;

 DBMS_OUTPUT.PUT_LINE(v_myrec.v_rec1.last_name ||' '||

        to_char(v_myrec.v_hire_date)||' '|| to_char(v_myrec.v_sal));

END;

/

<연습문제 6-1>

DECLARE

rec_coun countries%rowtype;

BEGIN

select * 

into rec_coun

from countries

where country_id = upper('&cid');

dbms_output.put_line('Country id : '||rec_coun.country_id||

chr(10) || 'Country name : ' || rec_coun.country_name||

chr(10) || 'Region : '|| rec_coun.region_id);

END;

/