【sql查询与优化】4.删除插入与更新

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SQL> select * from emp;

SQL> select * from dept t;

create table test(
 c1 varchar2(10) default '默认1',
 c2 varchar2(10) default '默认2',
 c3 varchar2(10) default '默认3',
 c4 date default sysdate
);

insert into test(c1,c2,c3) values(default,null,'手输值');

SQL> select * from test;

create or replace view v_test as select c1,c2,c3 from test;

insert into v_test(c1,c2,c3) values('手输c1',NULL,'勿改c4');

SQL> select * from test;

create table test2 as select * from test;

create table test2 as select * from test where 1=2;

SQL> desc test2

SQL> insert into test2 select * from test;

SQL> select * from test2;

SQL> alter table emp add constraints ch_sal check(sal>0);

SQL> alter table emp add constraints ch_hiredate check(hiredate>=sysdate);
alter table emp add constraints ch_hiredate check(hiredate>=sysdate)
                                                            *
第 1 行出现错误:
ORA-02436: 日期或系统变量在 CHECK 约束条件中指定错误

SQL> insert into
         (select empno,ename,hiredate
           from emp
          where hiredate <= sysdate with check option)
          values
          (9999,'test',sysdate+1);
      from emp
           *
第 3 行出现错误:
ORA-01402: 视图 WITH CHECK OPTIDN where 子句违规

SQL> insert into
         (select empno,ename,hiredate
           from emp
          where hiredate <= sysdate with check option)
          values
          (9999,'test',sysdate-1);

SQL> select * from emp e where e.hiredate like sysdate-1;

create table emp1 as select empno,ename,job from emp where 1=2;
create table emp2 as select empno,ename,deptno from emp where 1=2;

SQL> insert all
         into emp1(empno,ename,job) values(empno,ename,job)
         into emp2(empno,ename,deptno) values(empno,ename,deptno)
     select empno,ename,job,deptno from emp where deptno in (20,30);

SQL> select * from emp1;

SQL> select * from emp2;

SQL> delete emp1;
delete emp2;
insert all
    when job in('销售','会计') then
    into emp1(empno,ename,job) values(empno,ename,job)
    when deptno in ('20','30') then
    into emp2(empno,ename,deptno) values(empno,ename,deptno)
select empno,ename,job,deptno from emp;

SQL> select * from emp1;

SQL> select * from emp2;

SQL> delete emp1;
delete emp2;
/*有条件 insert first*/
insert first
    when job in('销售','会计') then
    into emp1(empno,ename,job) values(empno,ename,job)
    when deptno in ('20','30') then
    into emp2(empno,ename,deptno) values(empno,ename,deptno)
select empno,ename,job,deptno from emp;

SQL> select * from emp1;

SQL> select * from emp2;

SQL> create table t2 (d varchar(10),des varchar(50));

SQL> create table t1 as
          select '熊样，精神不佳' as d1,
                 '猫样，温驯听话' as d2,
                 '狗样，神气活现' as d3,
              '鸟样，向往明天' as d4,
              '花样，愿你快乐像花儿一样' as d5
           from dual;

SQL> select * from t1;

SQL> insert all
     into t2(d,des) values('周一',d1)
     into t2(d,des) values('周二',d2)
     into t2(d,des) values('周三',d3)
     into t2(d,des) values('周四',d4)
     into t2(d,des) values('周五',d5)
     select d1,d2,d3,d4,d5 from t1;

SQL> select * from t2;

SQL> alter table emp add dname varchar2(50) default 'noname';

SQL> update emp p
         set p.dname =
         (select dname
          from dept d where p.mgr=d.deptno
          and d.dname in ('管理部门','销售部门'));

SQL> select empno,ename,deptno,dname from emp;

SQL> roll back;

SQL> update emp p
         set p.dname =
         (select dname
          from dept d where p.mgr=d.deptno
          and d.dname in ('管理部门','销售部门'))
     where exists
         (select d.dname from dept d
            where d.deptno = p.mgr
            and d.dname in ('管理部门','销售部门'));

SQL> create table bonuses (employee_id number,bonus number default 100);

insert into bonuses
    (employee_id)
    (select e.employee_id
        from hr.employees e,oe.orders o
     where e.employee_id = o.sales_rep_id
     group by e.employee_id);
select * from bonuses order by employee_id;
commit;

merge into bonuses d
using (select employee_id,salary,department_id
       from hr.employess
       where department_id=80) s
on (d.employee_id=s.employss_id)
/*匹配条件d.employee_id=s.employee_id*/
when matched then/*当d表中存在与S对应数据时进行更新或删除*/
  update
     set d.bonus = d.bonus + s.salary * 0.01
  /*where只能出现一次，如果在这里加了where，delete后面的where就无效*/
  delete
     where (s.salary > 8000) /*删除时，只更新s.salary>8000时的数据*/
when not matched then/*当表中不存在与s对应的数据时进行新增*/
     insert
        (d.employee_id,d.bonus)
     values
        (s.employee_id,s.salary * 0.01)
     where (s.salary<=8000)/*新增时，只更新s.salary<=8000时的数据，注意这里与以前不同，是d表中不存在对应数据时才新增*/

SQL> create table dupes (id integer,name varchar(10));

insert into dupes values (1,'NBA');
insert into dupes values (2,'DNA');
insert into dupes values (3,'DNA');
insert into dupes values (4,'SINA');
insert into dupes values (5,'SUN');
insert into dupes values (6,'SUN');
insert into dupes values (7,'SUN');

delete
   from dupes a
where exists (select NULL from dupes b where b.name = a.name and b.id > a.id);

create index idx_name_id on dupes(name,id);

delete
   from dupes a
where exists (select NULL from dupes b where b.name = a.name and b.rowid > a.rowid);

create index idx_name on dupes(name);

SQL> select rowid as rid,
         name,
         row_number() over(partition by name order by id) as seq
       from dupes
     order by 2,3;

delete
    from dupes
  where rowid in (select rid
                 from (select rowid as rid,
                       row_number() over(partition by name order by id)as seq
                       from dupes)
                  where seq > 1);

【sql查询与优化】4.删除插入与更新

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原文地址：http://blog.csdn.net/acmman/article/details/51392417