oracle 필기시험 문제

1) A    100   .

　　Select　* FROM A Where A.COLUMN1 = A.COLUMN1

　　          ? (   ,  1       :)

　　(2) Create SEQUENCE PEAK_NO

　　Select PEAK_NO.NEXTVAL FROM DUAL -->     1

　　10   ,   


　　Select PEAK_NO.NEXTVAL FROM DUAL -->     ?

　　(3) SQL> connect sys as sysdba

　　Connected.


　　SQL> insert into dual values ( 'Y');

　　　　　1 row created.

　　SQL> commit;

　　　　　Commit complete.

　　SQL> select count(*) from dual;

　　　　　COUNT(*)

　　　　　----------

　　　　　2

　　SQL> delete from dual;

　　　　　commit;

　　　　　-->DUAL       ?

　　JUST TRY IT
      SQL   

   null    null，              


          ，          （   ：not in/not exists+null）
SQL> select * from usertable;
USERID USERNAME
----------- ----------------
1 user1
2 null
3 user3
4 null
5 user5
6 user6

SQL> select * from usergrade;
USERID USERNAME GRADE
---------- ---------------- ----------
1 user1 90
2 null 80
7 user7 80
8 user8 90
    ：

select count(*) from usergrade where username not in (select username from usertable);

select count(*) from usergrade g where not exists
(select null from usertable t where t.userid=g.userid and t.username=g.username);

   ：  1( 0 )   2 ( 3 )

A: 0 B:1 C:2 D:3 E:NULL


2

           ，          （   ：in/exists+rownum）
SQL> select * from usertable;
USERID USERNAME
----------- ----------------
1 user1
2 user2
3 user3
4 user4
5 user5

SQL> select * from usergrade;
USERNAME GRADE
---------------- ----------
user9 90
user8 80
user7 80
user2 90
user1 100
user1 80

    
Select count(*) from usertable t1 where username in
(select username from usergrade t2 where rownum <=1);

Select count(*) from usertable t1 where exists
(select 'x' from usergrade t2 where t1.username=t2.username and rownum <=1);

          ：( ) ( )
A: 0 B: 1 C: 2 D: 3

                 ，       ，    T1      ；
select * from emp;
EMPNO DEPTNO SALARY
----- ------ ------
100 1 55
101 1 50

select * from dept;
DEPTNO SUM_OF_SALARY
------ -------------
1 105
2

    ，         2   ，      null，  ，
        （  ）       （         ）         ，            ：

time session 1 session2
----------- ------------------------------- -----------------------------------
T1 insert into emp
values(102,2,60)

T2 update emp set deptno =2
where empno=100

T3 update dept set sum_of_salary =
(select sum(salary) from emp
where emp.deptno=dept.deptno)
where dept.deptno in(1,2);

T4 update dept set sum_of_salary =
(select sum(salary) from emp
where emp.deptno=dept.deptno)
where dept.deptno in(1,2);

T5 commit;

T6 select sum(salary) from emp group by deptno;
   ：    2      ：
T7 commit;
=======     ，        ，              ========

T8 select sum(salary) from emp group by deptno;
   ：       

T9 select * from dept;
   ：        

      ( )        ( )        ( )

A: B:
---------------- ----------------
1 50 1 50
2 60 2 55

C: D:
---------------- ----------------
1 50 1 115
2 115 2 50

E: F:
---------------- ----------------
1 105 1 110
2 60 2 55


          ，        （   ：    ）
select id,grade from student_grade
ID GRADE
-------- -----------
1 50
2 40
3 70
4 80
5 30
6 90

        
select id,grade from student_makeup
ID GRADE
-------- -----------
1 60
2 80
5 60

     dba                  ，   ：
update student_grade s set s.grade =
(select t.grade from student_makeup t
where s.id=t.id);
commit;
      ：
select GRADE from student_grade where id = 3;   ：

A: 0 B: 70 C: null D:      


                 ，       ，
    T1
session1 session2
-------------------------------------- ----------------------------------------
T1 select count(*) from t;
--    (1000) 

T2 delete from t where rownum <=100;

T3 begin
delete from t where rownum <=100;
commit;
end;
/

T4 truncate table t;

T5 select count(*) from t;
--          

A: 1000 B: 900 C: 800 D: 0