oracle查询语句
select * from scott.emp ;
1.–dense_rank()分析函数（查找每个部门工资最高前三名员工信息）
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：
–rank()分析函数(运行结果与上语句相同)
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：
–row_number()分析函数（运行结果与上相同）
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 ;
–rows unbounded preceding 分析函数（显示各部门的积累工资总和）
select deptno,sal,sum(sal) over(order by deptno asc rows unbounded preceding) 积累工资总和 from scott.emp ;
结果：
–rows 整数值 preceding(显示每最后4条记录的汇总值)
select deptno,sal,sum(sal) over(order by deptno rows 3 preceding) 每4汇总值 from scott.emp ;
结果：
–rows between 1 preceding and 1 following（统计3条记录的汇总值【当前记录居中】）
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：
–ratio_to_report(显示员工工资及占该部门总工资的比例)
select deptno,sal,ratio_to_report(sal) over(partition by deptno) 比例 from scott.emp ;
结果：
—查看所有用户
select * from dba_users ;
select count(*) from dba_users ;
select * from all_users ;
select * from user_users ;
select * from dba_roles ;
—查看用户系统权限
select * from dba_sys_privs ;
select * from user_users ;
—查看用户对象或角色权限
select * from dba_tab_privs ;
select * from all_tab_privs ;
select * from user_tab_privs ;
—查看用户或角色所拥有的角色
select * from dba_role_privs ;
select * from user_role_privs ;
— rownum:查询10至12信息
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：
–not exists；查询emp表在dept表中没有的数据
select * from scott.emp a where not exists(select * from scott.dept b where a.empno=b.deptno) ;
结果：
–rowid;查询重复数据信息
select * from scott.emp a where a.rowid>(select min(x.rowid) from scott.emp x where x.empno=a.empno);
—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)
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：
—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)
select * from(select a.*,row_number() over(order by empno desc) rk from scott.emp a ) where rk<10 and rk>=1;
结果：
–rownum分页(一万条数据，查询10000至9980时间大概在0.01秒左右)
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 ;
–left outer join:左连接
select a.*,b.* from scott.emp a left outer join scott.dept b on a.deptno=b.deptno ;
–right outer join:右连接
select a.*,b.* from scott.emp a right outer join scott.dept b on a.deptno=b.deptno ;
–inner join
select a.*,b.* from scott.emp a inner join scott.dept b on a.deptno=b.deptno ;
–full join
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 ;
–case when then end (交叉报表)
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：
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：
—交叉报表是使用分组函数与case结构一起实现
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 ;
–decode 函数
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 ;
–level。。。。connect by(层次查询)
select level,emp.* from scott.emp connect by prior empno = mgr order by level ;
结果：
–sys_connect_by_path函数
select ename,sys_connect_by_path(ename,’/’) from scott.emp start with mgr is null connect by prior empno=mgr ;
结果：
–start with connect by prior 语法
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 ;
–level与prior关键字
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：
—等值连接
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：
—非等值连接
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：
—自连接
select a.ename,a.sal,b.ename from scott.emp a,scott.emp b where a.mgr=b.empno ;
结果：
—左外连接
select a.ename,a.sal,b.ename from scott.emp a,scott.emp b where a.mgr=b.empno(+);
结果：
—多表连接
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：
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 ;
—单行子查询
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：
—单行子查询在 from 后
select scott.emp.*,(select deptno from scott.dept where loc=’new york’) a from scott.emp ;
—使用 in ,all,any 多行子查询
–in：表示等于查询出来的对应数据
select ename,job,sal,deptno from scott.emp where job in(select distinct job from scott.emp where deptno=10);
–all:表示大于所有括号中查询出来的对应的数据信息
select ename,sal,deptno from scott.emp where sal>all(select sal from scott.emp where deptno=30);
–any:表示大于括号查询出来的其中任意一个即可（只随机一个）
select ename,sal,deptno from scott.emp where sal>any(select sal from scott.emp where deptno=30);
—多列子查询
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);
—非成对比较
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);
—其他子查询
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)
);
–drop table test ;
select * from scott.test ;
–insert与子查询(表间数据的拷贝)
insert into scott.test(ename,job) select ename,job from scott.emp ;
–update与子查询
update scott.test set(ename,job)=(select ename,job from scott.emp where ename=’scott’ and deptno =’10’);
—创建表时，还可以指定列名
create table scott.test_1(ename,job) as select ename,job from scott.emp ;
select * from scott.test_1 ;
–delete与子查询
delete from scott.test where ename in(”);
—合并查询
–union语法（合并且去除重复行，且排序）
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 ;
–union all(直接将两个结果集合并，不排序)
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 ;
–intersect:取交集
select ename,sal,deptno from scott.emp where deptno>10 intersect select ename,sal,deptno from scott.emp where deptno<30;
—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
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：
—使用with得到以上同样的结果
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：
—分析函数
select ename,sal,sum(sal) over(partition by deptno order by sal desc) from scott.emp ;
–rows n preceding(窗口子句一)
select deptno,sal,sum(sal) over(order by sal rows 5 preceding) from scott.emp ;
结果：
–rum(..) over(..)..
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：
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：
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；
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 ;
–dense_rank():有重复的数字不跳着排列
–row_number()
select deptno,sal,row_number() over(partition by deptno order by sal) rm from scott.emp ;
结果：
–lag()和lead()
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：
–max(),min(),avg()
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：
–first_value(),last_value()
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：
—分组补充 group by grouping sets
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：
–rollup
select deptno,job,avg(sal) from scott.emp group by rollup(deptno,job) ;
—理解rollup等价于
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：
select deptno,job,avg(sal) a from scott.emp group by cube(deptno,job) ;
—理解cube
select deptno,job,avg(sal) from scott.emp group by cube(deptno,job) ;
—等价于
select deptno,job,avg(sal) from scott.emp group by grouping sets((deptno,job),(deptno),(job),());
结果：
—查询工资不在1500至2850之间的所有雇员名及工资
select ename,sal from scott.emp where sal not in(select sal from scott.emp where sal between 1500 and 2850 );
—部门10和30中的工资超过1500的雇员名及工资
select deptno,ename,sal from scott.emp a where a.deptno in(10,30) and a.sal>1500 order by sal desc ;
结果：
—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
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：
select * from scott.emp where hiredate >to_date(‘1981-02-01′,’yyyy-mm-dd’);
—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
select ename,sal,comm from scott.emp a where a.comm > all(0) order by comm desc;
—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）
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：
—查询公司每天，每月，每季度，每年的资金支出数额
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：
—查询所有员工的平均工资，总计工资，最高工资和最低工资
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：
—每种岗位的雇员总数和平均工资
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：
—雇员总数以及获得补助的雇员数
select count(*) as 公司雇员总数,count(comm) as 获得补助的雇员人数 from scott.emp ;
—管理者的总人数
—雇员工资的最大差额
select max(sal),min(sal),(max(sal) – min(sal)) as 员工工资最大差额 from scott.emp ;
—每个部门的平均工资
select deptno,avg(sal) from scott.emp a group by a.deptno;
结果：
—查询每个岗位人数超过2人的所有职员信息
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：
select * from scott.emp a where a.empno in(select mgr from scott.emp ) and (select count(mgr) from scott.emp)>2 ;
结果：
—处理重复行数据信息（删除，查找，修改）
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);
—查询emp表数据信息重复问题
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);
–initcap：返回字符串，字符串第一个字母大写
select initcap(ename) upp from scott.emp ;
结果：
–ascii:返回与指定的字符对应的十进制数
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：
–chr:给出整数，返回对应的字符
select chr(ascii(ename)) as 姓名 from scott.emp ;
结果：
–concat:连接字符串
select concat(a.ename,a.job)|| a.empno as 字符连接 from scott.emp a;
结果：
–instr: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
select instr(a.empno,a.mgr,1,1) from scott.emp a ;
–length:返回字符串的长度
select ename,length(a.ename) as 长度,a.job,length(a.job) as 长度 from scott.emp a ;
–lower：返回字符串，并将所返回的字符小写
select a.ename as 大写,lower(a.ename) as 小写 from scott.emp a ;
结果：
–upper：返回字符串，并将返回字符串都大写
select lower(a.ename) as 小写名字,upper(a.ename) as 大写名字 from scott.emp a ;
结果：
–rpad: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)
select lpad(rpad(a.ename,10,’*’),16,’*’) as 粘贴 from scott.emp a ;
结果：
–like不同角度的使用
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_’;
—每个部门的工资总和
select a.ename,sum(sal) from scott.emp a group by ename;
—每个部门的平均工资
select a.deptno,avg(sal) from scott.emp a group by deptno ;
—每个部门的最大工资
select a.deptno,max(sal) from scott.emp a group by deptno ;
—每个部门的最小工资
select a.deptno,min(sal) from scott.emp a group by deptno ;
—查询原工资占部门工资的比率
select deptno ,sal,ratio_to_report(sal) over(partition by deptno) sal_ratio from scott.emp ;
—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）
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：
—查询每个部门的平均工资
select distinct deptno,avg(sal) from scott.emp group by deptno order by deptno desc;
–union组合查出的结果，但要求查出来的数据类型必须相同
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 ;—只能从小到大
———创建表空间 要用拥有create tablespace权限的用户，比如sys
create tablespace tbs_dat datafile ‘c:\oradata\tbs_dat.dbf’ size 2000m;
———添加数据文件
alter tablespace tbs_dat add datafile ‘c:\oradata\tbs_dat2.dbf’ size 100m;
———改变数据文件大小
alter database datafile ‘c:\oradata\tbs_dat.dbf’ resize 250m;
———数据文件自动扩展大小
alter database datafile ‘c:\oradata\tbs_dat.dbf’ autoextend on next 1m maxsize 20m;
———修改表空间名称
alter tablespace tbs_dat rename to tbs_dat1;
———删除表空间 and datafiles 表示同时删除物理文件
drop tablespace tbs_dat including contents and datafiles;
–substr(s1,s2,s3)：截取s1字符串,从s2开始,结束s3
select substr(job,3,length(job)) from scott.emp ;
–replace：替换字符串
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’);
–soundex：返回一个与给定的字符串读音相同的字符串
select ename from scott.test where soundex(ename)=soundex(‘wether’);
–floor：取整数
select sal,floor(sal) as 整数 from scott.emp ;
–log（n,s）：返回一个以n为低，s的对数
select empno,log(empno,2) as 对数 from scott.emp ;
–mod(n1,n2)：返回一个n1除以n2的余数
select empno,mod(empno,2) as 余数 from scott.emp ;
结果：
–power(n1,n2)：返回n1的n2次方根
select empno,power(empno,2) as 方根 from scott.emp ;
–round和trunc：按照指定的精度进行舍入
select round(41.5),round(-41.8),trunc(41.6),trunc(-41.9) from scott.emp ;
–sign：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
select sign(45),sign(-21),sign(0) from scott.emp ;
结果：
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：
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