like 키워드의 간단한 사용

--         ,  ,  ,    
--    "  " 
--     :Sno,   char(9)-->        9        ;
--     :Sname,   varchar2(8)-->     2,3,4  ,                ;
--     :Sage,   smallint-->smallint        ,       ,-32,768-->32,767;
--     :Ssex,   char(2)-->           ,' '  ' ',    2         ;
--       :Sdept,   varchar2(4)-->              ,    4   ;
--            ;
create table Student
(
       Sno char(9) primary key,
       Sname varchar2(8),
       Ssex char(2) not null,
       Sage smallint not null,
       Sdept varchar2(4) not null
);

--    "  " 
--      :Cno,   char-->      4      ;
--      :Cname,   varchar2-->             ,         10   ,    20     ;
--        :Cpno,   char-->                        ;
--     :Ccredit,   smallint-->            ;
--  "  "      Cno;
--  "  "      Cpno;     Cpno        Cno;
create table Course
(
       Cno char(4) primary key,
       Cname varchar2(20) not null,
       Cpno char(4),
       Ccredit smallint not null,
       foreign key(Cpno) references Course(Cno)
);

--    "  " 
--     Sno,   char(9)-->      9        ;
--      Cno,   char(4)-->       4        ;
--     Grade,   smallint-->     0->100     ;
--      :Cno Sno   ;
--      :     Sno      Student    Sno;     Cno      Courses     Cno;
create table SC
(
       Sno char(9),
       Cno char(4),
       Grade smallint,
       primary key(Sno,Cno),
       foreign key(Sno) references Student(Sno),
       foreign key(Cno) references Course(Cno)
);

--            ，
--  value=ZHS16GBK，        2   ,       2      ;
--  value=AL32UTF8，        3   ,       3      ;
select * from v$nls_parameters t where t.PARAMETER='NLS_CHARACTERSET';
alter user scott account unlock;
alter user sys account unlock;
alteruseruser_name account unlock identifiedby  new_password;
--        value = ZHS16GBK,                      .

--         
insert into Student values('201215121','  ',' ',20,'CS');
insert into Student values('201215122','  ',' ',19,'CS');
insert into Student values('201215123','  ',' ',18,'MA');
insert into Student values('201215125','  ',' ',19,'IS');

--        
insert into Student values('201215121','  ',' ',20,'CS');
insert into Student values('201215122','  ',' ',19,'CS');

--        
insert into Student values(null,'  ',' ',19,'CS');
insert into Student values(null,'  ',' ',20,'IS');

--          
insert into Student values('201215126','  ',' ',null,'IS');
insert into Student values('201215126','  ',null,30,'IS');

--         
select * from Student;

--     
drop table Student;

--         
--       ,             -->  Cpno               ;
--       ,             -->           ,    ,        ;
insert into Course values('2','  ',null,2);
insert into Course values('6','    ',null,2);
insert into Course values('4','    ','6',3);
insert into Course values('7','PASCAl  ','6',4);
insert into Course values('5','    ','7',4);
insert into Course values('1','   ','5',4);
insert into Course values('3','    ','1',4);

--           
insert into Course values('1','   ','5',5);
insert into Course values('3','    ','1',4);

--         
insert into Course values(null,'   ','5',4);
insert into Course values(null,'    ','7',4);

--         
insert into Course values('8','    ','20',4);
insert into Course values('9','    ','11',4);

--           
insert into Course values('10','    ','7',null);
insert into Course values('13','    ','6',null);

--                            ,        
insert into Course values('2','  ',null,2);
insert into Course values('6','    ',null,2);

--           
select * from Course;

--     
drop table Course;

--         
--                ,                   ,          ;
--                  ,                           ;
--                         ,     
insert into SC values('201215121','1',92);
insert into SC values('201215121','2',85);
insert into SC values('201215121','3',88);
insert into SC values('201215122','2',90);
insert into SC values('201215122','3',80);

--insert into SC values('201215122','1',90);

--        ,                     
insert into SC values('201215122','9',100);
insert into SC values('201400644','1',70); 

--         ,             ,     
insert into SC values('201215122','3',90);
insert into SC values('201215121','1',92);

--        ,                
insert into SC values('201215122',null,90);
insert into SC values(null,'2',70);   

--           
select * from SC;     

--        
drop table SC;

--    
--  like            ,
--like          :[not]  like ''  [escape  ]
--                    .
--           ,         "%" ''_"   
--%          ,     0,     1.....(          0 ,1       )
--_         ,     1(        1   );

--     201215121        
select * 
from Student
where Sno like '201215121';

select * 
from Student
where Sno='201215121';

--      SQL           
--  like              ,     =   like  
select * 
from Student 
where Sno not like '201215121';

select * 
from Student 
where Sno!='201215121';

select * 
from Student
where Sno<>'201215121';
--    SQL           
--  like              ,    <>  !=   not like  

--             ,  ,  
select Sno      ,Sname      ,Ssex     
from Student
where Sname like ' %';

--                  ,  ,  
select Sname     ,Sno     ,Ssex     ,Sdept     
from Student
where Sname like ' _';

--  :      ASCII         _;     GBK      _;
select * from v$nls_parameters t where t.PARAMETER='NLS_CHARACTERSET';
--       GBk   ,     _ ,  _      ;

--     Course        
select * 
from Course;

--     Course     " "       4        
select Cno    ,Cname    ,Cpno      ,Ccredit   
from Course
where Cname like ' ___';

--     Course     " "          
select Cno    ,Cname    ,Cpno      ,Ccredit   
from Course
where Cname like ' %';

--     Course      " "          
select Cno    ,Cname    ,Cpno    ,Ccredit     
from Course
where Cname not like ' %';

--                  %  _,        escape  
--     Course        
select * 
from Course;

--             _     
insert into Course values('8','DB_Design','5',4);

--  DB_Design         
select Cno    ,Cname    ,Cpno      ,Ccredit      
from Course
where Cname like 'DB\_Design'  escape '\';

--  \        SQL            ,        ,            escape
--          \      ,            
select Cno    ,Cname    ,Cpno      ,Ccredit      
from Course
where Cname like 'DB$_Design'  escape '$'; 

select Cno    ,Cname    ,Cpno      ,Ccredit      
from Course
where Cname like 'DB#_Design'  escape '#';

select Cno    ,Cname    ,Cpno      ,Ccredit      
from Course
where Cname like 'DB@_Design'  escape '@';

select Cno    ,Cname    ,Cpno      ,Ccredit      
from Course
where Cname like 'DB#_Design' ;
--     SQL    ,             ,       \     ,  $,#,@     
--      escape    ,      ,  _        ,           

--   "DB_"  ,         i        
select Cno    ,Cname    ,Cpno      ,Ccredit     
from Course 
where Cname like 'DB@_%i__'  escape '@';

--  SQL              @, SQL        _          
--       %     _       @  ,