[b]Oracle[/b][b]查询语句[/b] select * from scott.emp ; [img]http://files.jb51.net/file_images/article/201308/oraclesql/image001.jpg[/img] [i]1.--dense_rank()[/i][i]分析函数（查找每个部门工资最高前三名员工信息）[/i] select * from (select deptno,ename,sal,dense_rank() over(partition by deptno order by sal desc) a from scott.emp) where a<=3 order by deptno asc,sal desc ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image002.jpg[/img] [i]--rank()[/i][i]分析函数(运行结果与上语句相同)[/i] select * from (select deptno,ename,sal,rank() over(partition by deptno order by sal desc) a from scott.emp ) where a<=3 order by deptno asc,sal desc ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image003.jpg[/img] [i]--row_number()[/i][i]分析函数（运行结果与上相同）[/i] select * from(select deptno,ename,sal,row_number() over(partition by deptno order by sal desc) a from scott.emp) where a<=3 order by deptno asc,sal desc ; [i]--rows unbounded preceding [/i][i]分析函数（显示各部门的积累工资总和）[/i] select deptno,sal,sum(sal) over(order by deptno asc rows unbounded preceding) 积累工资总和 from scott.emp ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image004.jpg[/img] [i]--rows [/i][i]整数值 preceding(显示每最后4条记录的汇总值)[/i] select deptno,sal,sum(sal) over(order by deptno rows 3 preceding) 每4汇总值 from scott.emp ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image005.jpg[/img] [i]--rows between 1 preceding and 1 following[/i][i]（统计3条记录的汇总值【当前记录居中】）[/i] select deptno,ename,sal,sum(sal) over(order by deptno rows between 1 preceding and 1 following) 汇总值 from scott.emp ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image006.jpg[/img] [i]--ratio_to_report([/i][i]显示员工工资及占该部门总工资的比例)[/i] select deptno,sal,ratio_to_report(sal) over(partition by deptno) 比例 from scott.emp ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image007.jpg[/img] [i]--[/i][i]查看所有用户[/i] select * from dba_users ; select count(*) from dba_users ; select * from all_users ; select * from user_users ; select * from dba_roles ; [i]--[/i][i]查看用户系统权限[/i] select * from dba_sys_privs ; select * from user_users ; [i]--[/i][i]查看用户对象或角色权限[/i] select * from dba_tab_privs ; select * from all_tab_privs ; select * from user_tab_privs ; [i]--[/i][i]查看用户或角色所拥有的角色[/i] select * from dba_role_privs ; select * from user_role_privs ; [i]-- rownum:[/i][i]查询10至12信息[/i] select * from scott.emp a where rownum<=3 and a.empno not in(select b.empno from scott.emp b where rownum<=9); 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image008.jpg[/img] [i]--not exists[/i][i]；查询emp表在dept表中没有的数据[/i] select * from scott.emp a where not exists(select * from scott.dept b where a.empno=b.deptno) ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image009.jpg[/img] [i]--rowid;[/i][i]查询重复数据信息[/i] select * from scott.emp a where a.rowid>(select min(x.rowid) from scott.emp x where x.empno=a.empno); [i]--[/i][i]根据rowid来分页(一万条数据，查询10000至9980时间大概在0.03秒左右)[/i] select * from scott.emp where rowid in(select rid from(select rownum rn,rid from(select rowid rid,empno from scott.emp order by empno desc) where rownum<10)where rn>=1)order by empno desc ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image010.jpg[/img] [i]--[/i][i]根据分析函数分页(一万条数据，查询10000至9980时间大概在1.01秒左右)[/i] select * from(select a.*,row_number() over(order by empno desc) rk from scott.emp a ) where rk<10 and rk>=1; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image011.jpg[/img] [i]--rownum[/i][i]分页(一万条数据，查询10000至9980时间大概在0.01秒左右)[/i] select * from(select t.*,rownum rn from(select * from scott.emp order by empno desc)t where rownum<10) where rn>=1; select * from(select a.*,rownum rn from (select * from scott.emp) a where rownum<=10) where rn>=5 ; [i]--left outer join:[/i][i]左连接[/i] select a.*,b.* from scott.emp a left outer join scott.dept b on a.deptno=b.deptno ; [i]--right outer join:[/i][i]右连接[/i] select a.*,b.* from scott.emp a right outer join scott.dept b on a.deptno=b.deptno ; [i]--inner join[/i] select a.*,b.* from scott.emp a inner  join scott.dept b on a.deptno=b.deptno ; [i]--full join [/i] select a.*,b.* from scott.emp a full join scott.dept b on a.deptno=b.deptno ; select a.*,b.* from scott.emp a,scott.dept b where a.deptno(+)=b.deptno ; select distinct ename,sal from scott.emp a group by sal having ; select * from scott.dept ; select * from scott.emp ; [i]--case when then end ([/i][i]交叉报表)[/i] select ename,sal,case deptno when 10 then '会计部' when 20 then '研究部' when 30 then '销售部' else '其他部门' end 部门 from scott.emp ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image012.jpg[/img] select ename,sal,case when sal>0 and sal<1500 then '一级工资' when sal>=1500 and sal<3000 then '二级工资' when sal>=3000 and sal<4500 then '三级工资' else '四级工资' end 工资等级 from scott.emp order by sal desc ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image013.jpg[/img] [i]--[/i][i]交叉报表是使用分组函数与case结构一起实现[/i] select 姓名,sum(case 课程 when '数学' then 分数 end)数学,sum(case 课程 when '历史' then 分数 end)历史 from 学生 group by 姓名 ; [i]--decode [/i][i]函数[/i] select 姓名,sum(decode(课程,'数学',分数,null))数学,sum(decode(课程,'语文',分数,null))语文,sum(decode(课程,'历史','分数',null))历史 from 学生 group by 姓名 ; [i]--level[/i][i]。。。。connect by(层次查询)[/i] select level,emp.* from scott.emp connect by prior empno = mgr order by level ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image014.jpg[/img] [i]--sys_connect_by_path[/i][i]函数[/i] select ename,sys_connect_by_path(ename,'/') from scott.emp start with mgr is null connect by prior empno=mgr ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image015.jpg[/img] [i]--start with connect by prior [/i][i]语法[/i] select lpad(ename,3*(level),'')姓名,lpad(ename,3*(level),'')姓名 from scott.emp where job<>'CLERK' start with mgr is null connect by prior mgr = empno ; [i]--level[/i][i]与prior关键字[/i] select level,emp.* from scott.emp start with ename='SCOTT' connect by prior empno=mgr; select level,emp.* from scott.emp start with ename='SCOTT' connect by empno = prior mgr ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image016.jpg[/img] [i]--[/i][i]等值连接[/i] select empno,ename,job,sal,dname from scott.emp a,scott.dept b where a.deptno=b.deptno and (a.deptno=10 or sal>2500); 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image017.jpg[/img] [i]--[/i][i]非等值连接[/i] select a.ename,a.sal,b.grade from scott.emp a,scott.salgrade b where a.sal between b.losal and b.hisal ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image018.jpg[/img] [i]--[/i][i]自连接[/i] select a.ename,a.sal,b.ename from scott.emp a,scott.emp b where a.mgr=b.empno ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image019.jpg[/img] [i]--[/i][i]左外连接[/i] select a.ename,a.sal,b.ename from scott.emp a,scott.emp b where a.mgr=b.empno(+); 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image020.jpg[/img] [i]--[/i][i]多表连接[/i] select * from scott.emp ,scott.dept,scott.salgrade where scott.emp.deptno=scott.dept.deptno and scott.emp.sal between scott.salgrade.losal and scott.salgrade.hisal ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image021.jpg[/img] select * from scott.emp a join scott.dept b on a.deptno=b.deptno join scott.salgrade s on a.sal between s.losal and s.hisal where a.sal>1000; select * from(select * from scott.emp a join scott.dept b on a.deptno=b.deptno where a.sal>1000) c join scott.salgrade s on c.sal between s.losal and s.hisal ; [i]--[/i][i]单行子查询[/i] select * from scott.emp a where a.deptno=(select deptno from scott.dept where loc='NEW YORK'); select * from scott.emp a where a.deptno in (select deptno from scott.dept where loc='NEW YORK'); 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image022.jpg[/img] [i]--[/i][i]单行子查询在 from 后[/i] select scott.emp.*,(select deptno from scott.dept where loc='NEW YORK') a from scott.emp ; [i]--[/i][i]使用 in ,all,any 多行子查询[/i] [i]--in[/i][i]：表示等于查询出来的对应数据[/i] select ename,job,sal,deptno from scott.emp where job in(select distinct job from scott.emp where deptno=10); [i]--all:[/i][i]表示大于所有括号中查询出来的对应的数据信息[/i] select ename,sal,deptno from scott.emp where sal>all(select sal from scott.emp where deptno=30); [i]--any:[/i][i]表示大于括号查询出来的其中任意一个即可（只随机一个）[/i] select ename,sal,deptno from scott.emp where sal>any(select sal from scott.emp where deptno=30); [i]--[/i][i]多列子查询[/i] select ename,job,sal,deptno from scott.emp where(deptno,job)=(select deptno,job from scott.emp where ename='SCOTT'); select ename,job,sal,deptno from scott.emp where(sal,nvl(comm,-1)) in(select sal,nvl(comm,-1) from scott.emp where deptno=30); [i]--[/i][i]非成对比较[/i] select ename,job,sal,deptno from scott.emp where sal in(select sal from scott.emp where deptno=30) and nvl(comm,-1) in(select nvl(comm,-1) from scott.emp where deptno=30); [i]--[/i][i]其他子查询[/i] select ename,job,sal,deptno from scott.emp where exists(select null from scott.dept where scott.dept.deptno=scott.emp.deptno and scott.dept.loc='NEW YORK'); select ename,job,sal from scott.emp join(select deptno,avg(sal) avgsal,null from scott.emp group by deptno) dept on emp.deptno=dept.deptno where sal>dept.avgsal ; create table scott.test(        ename varchar(20),        job varchar(20) ); [i]--drop table test ;[/i] select * from scott.test ; [i]--Insert[/i][i]与子查询(表间数据的拷贝)[/i] insert into scott.test(ename,job) select ename,job from scott.emp ; [i]--Update[/i][i]与子查询[/i] update scott.test set(ename,job)=(select ename,job from scott.emp where ename='SCOTT' and deptno ='10'); [i]--[/i][i]创建表时，还可以指定列名[/i] create table scott.test_1(ename,job) as select ename,job from scott.emp ; select * from scott.test_1 ; [i]--delete[/i][i]与子查询[/i] delete from scott.test where ename in(''); [i]--[/i][i]合并查询[/i] [i]--union[/i][i]语法（合并且去除重复行，且排序）[/i] select ename,sal,deptno from scott.emp where deptno>10 union select ename,sal,deptno from scott.emp where deptno<30 ; select a.deptno from scott.emp a union select b.deptno from scott.dept b ; [i]--union all([/i][i]直接将两个结果集合并，不排序)[/i] select ename,sal,deptno from scott.emp where deptno>10 union all select ename,sal,deptno from scott.emp where deptno<30 ; select a.deptno from scott.emp a union all select b.deptno from scott.dept b ; [i]--intersect:[/i][i]取交集[/i] select ename,sal,deptno from scott.emp where deptno>10 intersect select ename,sal,deptno from scott.emp where deptno<30; [i]--[/i][i]显示部门工资总和高于雇员工资总和三分之一的部门名及工资总和[/i] select dname as 部门,sum(sal) as 工资总和 from scott.emp a,scott.dept b where a.deptno=b.deptno group by dname having sum(sal)>(select sum(sal)/3 from scott.emp c,scott.dept d where c.deptno=d.deptno); 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image023.jpg[/img] [i]--[/i][i]使用with得到以上同样的结果[/i] with test as (select dname ,sum(sal) sumsal  from scott.emp ,scott.dept where scott.emp.deptno=scott.dept.deptno group by dname) select dname as 部门,sumsal as 工资总和 from scott.test where sumsal>(select sum(sumsal)/3 from scott.test); 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image024.jpg[/img] [i]--[/i][i]分析函数[/i] select ename,sal,sum(sal) over(partition by deptno order by sal desc) from scott.emp ; [i]--rows n preceding([/i][i]窗口子句一)[/i] select deptno,sal,sum(sal) over(order by sal rows 5 preceding) from scott.emp ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image025.jpg[/img] [i]--rum(..) over(..)..[/i] select sal,sum(1) over(order by sal) aa from scott.emp  ; select deptno,ename,sal,sum(sal) over(order by ename) 连续求和,sum(sal) over() 总和,100*round(sal/sum(sal) over(),4) as 份额 from scott.emp; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image026.jpg[/img] select deptno,ename,sal,sum(sal) over(partition by deptno order by ename) 部门连续求和,sum(sal) over(partition by deptno) 部门总和,100*round(sal/sum(sal) over(),4) as 总份额 from scott.emp; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image027.jpg[/img] select deptno,sal,rank() over (partition by deptno order by sal),dense_rank() over(partition by deptno order by sal) from scott.emp order by deptno ; 结果； [img]http://files.jb51.net/file_images/article/201308/oraclesql/image028.jpg[/img] select * from (select rank() over(partition by 课程 order by 分数 desc) rk,分析函数_rank.* from 分析函数_rank) where rk<=3 ; [i]--dense_rank():[/i][i]有重复的数字不跳着排列[/i] [i]--row_number()[/i] select deptno,sal,row_number() over(partition by deptno order by sal) rm from scott.emp ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image029.jpg[/img] [i]--lag()[/i][i]和lead()[/i] select deptno,sal,lag(sal) over(partition by deptno order by sal) 上一个,lead(sal) over(partition by deptno order by sal) from scott.emp ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image030.jpg[/img] [i]--max(),min(),avg()[/i] select deptno,sal,max(sal) over(partition by deptno order by sal)最大,min(sal) over(partition by deptno order by sal)最小,avg(sal) over(partition by deptno order by sal)平均 from scott.emp ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image031.jpg[/img] [i]--first_value(),last_value()[/i] select deptno,sal,first_value(sal) over(partition by deptno)最前,last_value(sal) over(partition by deptno )最后 from scott.emp ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image032.jpg[/img] [i]--[/i][i]分组补充 group by grouping sets[/i] select deptno ,sal,sum(sal) from scott.emp group by grouping sets(deptno,sal); select null,sal,sum(sal) from scott.emp group by sal union all select deptno,null,sum(sal) from scott.emp group by deptno ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image033.jpg[/img] [i]--rollup[/i] select deptno,job,avg(sal) from scott.emp group by rollup(deptno,job) ; [i]--[/i][i]理解rollup等价于[/i] select deptno,job,avg(sal) from scott.emp group by deptno,job union select deptno ,null,avg(sal) from scott.emp group by deptno union select null,null,avg(sal) from scott.emp ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image034.jpg[/img] select deptno,job,avg(sal) a from scott.emp group by cube(deptno,job) ; [i]--[/i][i]理解CUBE[/i] select deptno,job,avg(sal) from scott.emp group by cube(deptno,job) ; [i]--[/i][i]等价于[/i] select deptno,job,avg(sal) from scott.emp group by grouping sets((deptno,job),(deptno),(job),()); 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image035.jpg[/img] [i]--[/i][i]查询工资不在1500至2850之间的所有雇员名及工资[/i] select ename,sal from scott.emp where sal not in(select sal from scott.emp where sal between 1500 and 2850 ); [i]--[/i][i]部门10和30中的工资超过1500的雇员名及工资[/i] select deptno,ename,sal from scott.emp a where a.deptno in(10,30) and a.sal>1500 order by sal desc ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image036.jpg[/img] [i]--[/i][i]在1981年2月1日至1981年5月1日之间雇佣的雇员名，岗位及雇佣日期，并以雇佣日期先后顺序排序[/i] select ename as 姓名,job as 岗位,hiredate as 雇佣日期 from scott.emp a where a.hiredate between to_date('1981-02-01','yyyy-mm-dd') and to_date('1981-05-01','yyyy-mm-dd') order by a.hiredate asc ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image037.jpg[/img] select * from scott.emp where hiredate >to_date('1981-02-01','yyyy-MM-dd'); [i]--[/i][i]查询获得补助的所有雇佣名，工资及补助额，并以工资和补助的降序排序[/i] select ename,sal,comm from scott.emp a where a.comm > all(0) order by comm desc; [i]--[/i][i]工资低于1500的员工增加10%的工资，工资在1500及以上的增加5%的工资并按工资高低排序（降序）[/i] select ename as 员工姓名,sal as 补发前的工资,case when sal<1500 then (sal+sal*0.1) else (sal+sal*0.05) end 补助后的工资 from scott.emp order by sal desc ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image038.jpg[/img] [i]--[/i][i]查询公司每天，每月，每季度，每年的资金支出数额[/i] select sum(sal/30) as 每天发的工资,sum(sal) as 每月发的工资,sum(sal)*3 as 每季度发的工资,sum(sal)*12 as 每年发的工资 from scott.emp; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image039.jpg[/img] [i]--[/i][i]查询所有员工的平均工资，总计工资，最高工资和最低工资[/i] select avg(sal) as 平均工资,sum(sal) as 总计工资,max(sal) as 最高工资,min(sal) as 最低工资 from scott.emp; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image040.jpg[/img] [i]--[/i][i]每种岗位的雇员总数和平均工资[/i] select job as 岗位,count(job) as 岗位雇员总数,avg(sal) as 平均工资 from scott.emp group by job order by 平均工资 desc; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image041.jpg[/img] [i]--[/i][i]雇员总数以及获得补助的雇员数[/i] select count(*) as 公司雇员总数,count(comm) as 获得补助的雇员人数 from scott.emp ; [i]--[/i][i]管理者的总人数[/i] [i]--[/i][i]雇员工资的最大差额[/i] select max(sal),min(sal),(max(sal) - min(sal)) as 员工工资最大差额 from scott.emp ; [i]--[/i][i]每个部门的平均工资[/i] select deptno,avg(sal) from scott.emp a group by a.deptno; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image042.jpg[/img] [i]--[/i][i]查询每个岗位人数超过2人的所有职员信息[/i] select * from scott.emp a,(select c.job,count(c.job) as sl from scott.emp c group by c.job ) b where b.sl>2 and a.job=b.job; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image043.jpg[/img] select * from scott.emp a where a.empno in(select mgr from scott.emp ) and (select count(mgr) from scott.emp)>2 ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image044.jpg[/img] [i]--[/i][i]处理重复行数据信息（删除，查找，修改）[/i] select * from a1 a where not exists (select b.rd from (select rowid rd,row_number() over(partition by LOAN, BRANCH order by BEGIN_DATE desc) rn from a1) b where b.rn = 1 and a.rowid = b.rd); [i]--[/i][i]查询emp表数据信息重复问题[/i] select * from scott.emp a where exists(select b.rd from(select rowid rd,row_number() over(partition by ename,job,mgr,hiredate,sal,comm,deptno order by empno asc) rn from scott.emp) b where b.rn=1 and a.rowid=b.rd); [i]--initcap[/i][i]：返回字符串，字符串第一个字母大写[/i] select initcap(ename) Upp from scott.emp ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image045.jpg[/img] [i]--ascii:[/i][i]返回与指定的字符对应的十进制数[/i] select ascii(a.empno) as 编号,ascii(a.ename) as 姓名,ascii(a.job) as 岗位 from scott.emp a ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image046.jpg[/img] [i]--chr:[/i][i]给出整数，返回对应的字符[/i] select chr(ascii(ename)) as 姓名 from scott.emp ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image047.jpg[/img] [i]--concat:[/i][i]连接字符串[/i] select concat(a.ename,a.job)|| a.empno as 字符连接 from scott.emp a; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image048.jpg[/img] [i]--instr:[/i][i]在一个字符串中搜索指定的字符,返回发现指定的字符的位置[/i] select instr(a.empno,a.mgr,1,1) from scott.emp a ; [i]--length:[/i][i]返回字符串的长度[/i] select ename,length(a.ename) as 长度,a.job,length(a.job) as 长度 from scott.emp a ; [i]--lower[/i][i]：返回字符串，并将所返回的字符小写[/i] select a.ename as 大写,lower(a.ename) as 小写 from scott.emp a ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image049.jpg[/img] [i]--upper[/i][i]：返回字符串，并将返回字符串都大写[/i] select lower(a.ename) as 小写名字,upper(a.ename) as 大写名字 from scott.emp a ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image050.jpg[/img] [i]--rpad:[/i][i]在列的右边粘贴字符，lpad: 在列的左边粘贴字符(不够字符则用*来填满)[/i] select lpad(rpad(a.ename,10,'*'),16,'*') as 粘贴 from scott.emp a ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image051.jpg[/img] [i]--like[/i][i]不同角度的使用[/i] select * from scott.emp where ename like '%XXR%'; select * from scott.emp where ename like '%S'; select * from scott.emp where ename like 'J%'; select * from scott.emp where ename like 'S'; select * from scott.emp where ename like '%S_'; [i]--[/i][i]每个部门的工资总和[/i] select a.ename,sum(sal) from scott.emp a group by ename; [i]--[/i][i]每个部门的平均工资[/i] select a.deptno,avg(sal) from scott.emp a group by deptno ; [i]--[/i][i]每个部门的最大工资[/i] select a.deptno,max(sal) from scott.emp a group by deptno ; [i]--[/i][i]每个部门的最小工资[/i] select a.deptno,min(sal) from scott.emp a group by deptno ; [i]--[/i][i]查询原工资占部门工资的比率[/i] select deptno ,sal,ratio_to_report(sal) over(partition by deptno) sal_ratio from scott.emp ; [i]--[/i][i]查询成绩不及格的所有学生信息（提示：没有对应的表，只是意思意思。不及格人数大于等于三才能查）[/i] select * from scott.emp where empno in(select distinct empno from scott.emp where 3<(select count(sal) from scott.emp where sal<3000) and empno in(select empno from scott.emp where sal<3000)); 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image052.jpg[/img] [i]--[/i][i]查询每个部门的平均工资[/i] select distinct deptno,avg(sal) from scott.emp group by deptno  order by deptno desc; [i]--union[/i][i]组合查出的结果，但要求查出来的数据类型必须相同[/i] select sal from scott.emp where sal >=all(select sal from scott.emp ) union select sal from scott.emp ; select * from scott.emp a where a.empno between 7227 and 7369 ;[i]--[/i][i]只能从小到大[/i] [i]---------[/i][i]创建表空间  要用拥有create tablespace权限的用户，比如sys[/i] create tablespace tbs_dat datafile 'c:\oradata\tbs_dat.dbf' size 2000M; [i]---------[/i][i]添加数据文件[/i] alter tablespace tbs_dat add datafile 'c:\oradata\tbs_dat2.dbf' size 100M; [i]---------[/i][i]改变数据文件大小[/i] alter database datafile 'c:\oradata\tbs_dat.dbf' resize 250M; [i]---------[/i][i]数据文件自动扩展大小[/i] alter database datafile 'c:\oradata\tbs_dat.dbf' autoextend on next 1m maxsize 20m; [i]---------[/i][i]修改表空间名称[/i] alter tablespace tbs_dat rename to tbs_dat1; [i]---------[/i][i]删除表空间  and datafiles 表示同时删除物理文件[/i] drop tablespace tbs_dat including contents and datafiles; [i]--substr(s1,s2,s3)[/i][i]：截取s1字符串,从s2开始,结束s3[/i] select substr(job,3,length(job)) from scott.emp ; [i]--replace[/i][i]：替换字符串[/i] select replace(ename,'LL','aa') from scott.emp; select * from scott.test; insert into scott.test(ename,job) values('weather','好'); insert into scott.test(ename,job) values('wether','差'); [i]--soundex[/i][i]：返回一个与给定的字符串读音相同的字符串[/i] select ename from scott.test where soundex(ename)=soundex('wether'); [i]--floor[/i][i]：取整数[/i] select sal,floor(sal) as 整数 from scott.emp ; [i]--log[/i][i]（n,s）：返回一个以n为低，s的对数[/i] select empno,log(empno,2) as 对数 from scott.emp ; [i]--mod(n1,n2)[/i][i]：返回一个n1除以n2的余数[/i] select empno,mod(empno,2) as 余数 from scott.emp ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image053.jpg[/img] [i]--power(n1,n2)[/i][i]：返回n1的n2次方根[/i] select empno,power(empno,2) as 方根 from scott.emp ; [i]--round[/i][i]和trunc：按照指定的精度进行舍入[/i] select round(41.5),round(-41.8),trunc(41.6),trunc(-41.9) from scott.emp ; [i]--sign[/i][i]：取数字n的符号,大于0返回1,小于0返回-1,等于0返回0[/i] select sign(45),sign(-21),sign(0) from scott.emp ; 结果： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image054.jpg[/img] select * from scott.emp; oracle相关的数据库SQL查询语句： 1.  在职员表中查询出基本工资比平均基本工资高的职工编号。 2.  查询一个或者多个部门的所有员工信息，该部门的所有员工工资都高于公司的平均工资。 3.  现有张三的出生日期：1985-01-15 01:27:36，请各自新建表，将此日期时间插入表中，并计算出张三的年龄，显示张三的生日。 4.  生日的输出格式要求为MM-DD（未满两位的用0不全），张三的生日为01-15。 5.  算年龄要求用三个方式实现。 6.  生日要求用两个方式实现。 7.  在数据库表中有以下字符数据，如： 13-1,14-2,13-15，13-2，13-108，13-3，13-10,13-200,13-18,100-11,14-1 现在希望通过一条SQL语句进行排序，并且首先要按照前半部分的数字进行排序，然后再按照后半部分的数字进行排序，输出要拍成如下所示： 13-1,13-2,13-3,13-10,13-15,13-18,13-108,13-200,14-1,14-2,100-11 数据库表名：SellRecord;字段ListNumber; 8.  显示所有雇员的姓名以及满10年服务年限后的日期。 9.  显示雇员姓名，根据其服务年限，将最老的雇员排在最前面。 10显示所有雇员的姓名和加入公司的年份和月份，按雇员受雇日期所在月排序，将最早年份的职员排在最前面。 10.             显示假设一个月为30天的情况下所有雇员的日薪金。 11.             找出在（任何年份的）2月受聘的所有雇员（用两种方式实现）。 12.             对于每个雇员，显示其加入公司的天数。 13.             以年，月和日的方式显示所有雇员的服务年限（入职多少年/入职了多少月/入职了多少天）。 14.             找出各月最后一天受雇的所有雇员。 15.             找出早于25年之前受雇的雇员（用两种方式实现）。 16.             工资最低1500的职员增加10%，1500以上的增加5%的工资，用一条update语句实现（用两种方式实现）。 17.             按照部门统计每种岗位的平均工资，要求输出的格式如下图所示： [img]http://files.jb51.net/file_images/article/201308/oraclesql/image055.jpg[/img] 18. [img]http://files.jb51.net/file_images/article/201308/oraclesql/image056.jpg[/img] 19. [img]http://files.jb51.net/file_images/article/201308/oraclesql/image057.jpg[/img] 20. [img]http://files.jb51.net/file_images/article/201308/oraclesql/image058.jpg[/img] 21,。 [img]http://files.jb51.net/file_images/article/201308/oraclesql/image059.jpg[/img] 22. [img]http://files.jb51.net/file_images/article/201308/oraclesql/image060.jpg[/img] 本人声明：以上内容出现任何错误与不足，皆与本人无关。