SQL文Oracleデータベースの基本的な削除

sql文は多くの場合データベースで共通していますが、異なるデータベースでは部分的な違いがあるので、今日はsqlの
Oracleの基本的なアプリケーションは、以下の例を参照してください.

--  
create table person(username varchar2(20),userage number(10),usersex char(2));

--     
desc person;

--          null
alter table person modify(userage number(10) not null);

--       
select * from person;

--          
select * from tab;

--    (          ，        ）
insert into person(username,userage,usersex)values('  ',20,' ');

--    （       ，           ）
insert into person values('  ',30,' ');

--    (      where  ，     username   ）
update person set username='  'where username='  ';

--        
delete person;

--       
delete person where username='  '; 


----------------------------------------------------------------------    

--           
select * from emp;

--       (                  ）
select empno,ename from emp;

--          
select distinct job from emp;

--    (        ，  ，  ）(     )
select deptno,job,sal from emp where ename='SMITH';




--    （       10 20    ）
select * from emp where deptno=10 or deptno=20;

--    （      2000    2500）
select * from emp where sal>2000 and sal<2500;



--               (  %               _           )
select * from emp where ename like '%K%';

--      S   
select * from emp where ename like 'S%';

--        O   
select * from emp where ename like '__O%';

-- where   in
--         (7369,7566)
select * from emp where empno in(7369,7566);


--         
select * from emp where mgr is null;

--     (as    )
select empno as   ,ename as   ,sal as    from emp where ename like 'S%';

--  smith      
select empno   ,ename   ,sal*12    from emp where ename='SMITH';

--      1000     MANAGER，      J   
select * from emp where (sal<1000 or job='MANAGER') and ename like 'J%';

--       ，              (desc      ； asc     )
select * from emp order by sal desc;
select * from emp order by sal asc;

--         ，  ，  （  +  ）     nvl(comm,0)   comm null    0     
select empno   ,ename   ,sal*12+nvl(comm,0)    from emp;

--       
select empno   ,ename   ,sal*12+nvl(comm,0)    from emp order by    desc;

----------      max  min  avg  sum  count

--         
select max(sal)    from emp;

--                 
select empno   ,ename   ,sal    from emp where sal=(select max(sal)    from emp); --  
select empno   ,ename   ,sal    from emp where sal=(select min(sal)    from emp); --  
select empno   ,ename   ,sal    from emp where sal=(select max(sal)    from emp) or sal=(select min(sal)    from emp);--       

--         
select  avg(sal)      from emp;
select sum(sal)/count(empno)      from emp;
--       
select count(empno)     from emp;
--           
select sum(sal)      from emp;


------------    
--group by
--                
--             
select max(sal)     ,avg(sal)     ,deptno    from emp group by deptno;

--                    
select avg(sal)     ,min(sal)     ,job   ,deptno    from emp group by job,deptno order by deptno;

--        2000                       having
select avg(sal)     ,deptno    from emp group by deptno having avg(sal)<2000;

--        2000          ，        
select deptno   ,avg(sal)      from emp where deptno!=10 group by deptno having avg(sal)>2000 order by avg(sal);


-------------------------------------------------------------------------------------------------    
--     
select * from dept;

--    ,        
select e.ename   ,e.sal   ,d.dname      from emp e,dept d where e.deptno=d.deptno;

--      10    ，   ，  
select e.ename   ,e.sal   ,d.dname      from emp e,dept d where e.deptno=d.deptno and e.deptno=10;

--        ，  ，                   
select e.ename,e.sal,s.grade from emp e,salgrade s where e.sal between s.losal and s.hisal;

--      ，    ，       ，        
select e.ename,e.sal,d.dname from emp e,dept d where e.deptno=d.deptno order by e.deptno desc;

-----   


1、	--    30      

2、	select * from emp where deptno = 30;

3、	--        （CLERK）   ，  ，     。

4、	select empno,ename,deptno from emp where job = 'CLERK';

5、	--           

6、	select * from emp where comm>sal;

7、	--        60%   

8、	select * from emp where comm>sal*0.6;

9、	--    10         20           

10、	select * from emp where deptno =10 and job = 'MANAGER' or deptno =20 and job = 'CLERK';

11、--	    10         20      ，                  2000        

12、	select * from emp where deptno =10 and job = 'MANAGER' or deptno =20 and job = 'CLERK' or job!='MANAGER' and job!='CLERK'and sal>=2000;
13、--	              ；

14、	select distinct job from emp where comm is not null;

15、--	             100   ；

16、	select * from emp where comm<100;

19、--	    12       
20、	select * from emp where hiredate <'1-1  2012';

27、	--       

28、	select * from emp where ename like 'A%';

35、--	      “A”   

36、	select * from emp where ename like '%A%';

これらの使い方には、oracleデータベースの基本的な削除変更機能が含まれています.