Oracle SQL用法_Oracle教程

　　
这个是对于Oracle数据库的sql基本语句，
SQL plus执行通过的
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select empno, to_char(sal,'999,999.99') sal from emp;
select distinct deptno from emp;
select empno,ename,sal*0.5 from emp where deptno=10;
select empno''ename,nvl(sal,0)+nvl(comm,0) from emp;
select empno,ename,job,sal from emp where empno=&empno;
select sysdate,user,uid,rowid,rownum from emp;
[sysdate,user,uid,rowid,rownum为伪列]
select empno,ename,comm from emp where comm=null;
[comm is null];
select empno,ename,nvl(comm,"0") from emp where comm is null;
select deptno,dname from dept where deptno in(30,40);
select deptno,dname,loc from dept where loc not in('NEW YORK','CHICAGO');
select deptno,ename,sal from emp where deptno=10 or deptno=20 and sal>3000;
[列别名]
select e.ename EMPLOYEE,e.sal*1.15 NEW_SAl from emp e where e.deptno=10;
[多表连接]
select d.dname,e.ename,e.sal,e.comm from emp e,dept d where d.deptno=e.deptno order by d.deptno;
[使用子查询]
select ename from emp where deptno=(select deptno from dept where dname='SALES');
[查询别名]
select e.ename,d.dname,e.deptno'=='d.deptno from emp e,
(select deptno,dname from dept where loc='NEW YORK') d
where e.deptno=d.deptno
order by d.deptno;
[union:联合]
select ename,sal,comm from emp
union
select 'TOTAL',sum(sal),sum(comm) from emp order by sal

ENAME            SAL      COMM
---------- --------- ---------
SMITH            800
JAMES            950
ADAMS           1100
SCOTT           3000
KING            5000
TOTAL          29025      2200
------------------------------
[intersect:相交]
select ename,sal,comm from emp where sal>1300
INTERSECT
select ename,sal,comm from emp where comm is not null
===select ename,sal,comm from emp where sal>1300 and comm is not null

ENAME            SAL      COMM
---------- --------- ---------
ALLEN           1600       300
TURNER
       1500         0
------------------------------
[minus]
select ename,sal comm from emp where sal>1300
minus
select ename,sal comm from emp where sal>1500;
===select ename,sal,comm from emp where sal>1300 and not(sal>1500)
ENAME           COMM
---------- ---------
TURNER          1500
--------------------
select to_char(sysdate,'yyyy/mm/dd hh24:mi') sys_date from dual;
select to_date('2002/08/13','yyyy/mm/dd') from dual;
select to_number('12345',99999) from dual;
select empno,ename from emp where months_between(sysdate,hiredate)>=12;
    add_months(date,number)
    last_day(date)
    months_between(date1,date2)
    next_dat(date,day)
    round(date,format)
    trunc(date,format)
---------------------
数值函数
    abs(number)
    ceil(number)
    cos(number)
    ln(number)
    mod(n,m)
    round(number,decimal_digits)
    sign(number)
    sqrt(number)
    sin(number)
-------------------
字符函数
    ascii(character)
    chr(number)
    concat(string1,string2) #
    initcap(string)
    length(string)
    lower(string)   upper(string)
    substr(string,start[,length])
    replace(string,search_string,replace_string)
-------------------
other
     greatest(list of values)
     least(list of values)
     nvl(eXPression,replacement_value)
     AVG(expression)
     COUNT(expression)
     MAX(expression)
     MIN(expression)
     SUM(expression)
Welcome>select count(*),sum(sal),avg(sal),max(sal),min(sal) from emp;

COUNT(*) SUM(SAL) AVG(SAL) MAX(SAL) MIN(SAL)
--------- --------- --------- --------- ---------
       14     29025 2073.2143      5000       800
---------------------------------------------------------------------------
[右连接：如下图，假如出现条件不符和的，以左边为主/e.deptno/,右边的/d.deptno/应该以空行还填补左边显示的内容]
select d.dname,e.ename from emp e,dept d where e.deptno=d.deptno(+) order by d.dname,e.ename；

1 select d.dname D_Dname,e.ename E_Ename,d.deptno D_Deptno,e.deptno E_Deptno from emp e,dept d
2* where e.deptno=d.deptno(+) order by d.dname,e.ename
Welcome>/

D_DNAME        E_ENAME     D_DEPTNO E_DEPTNO
-------------- ---------- --------- ---------
ACCOUNTING     CLARK             10        10
ACCOUNTING     KING              10        10
ACCOUNTING     MILLER            10        10
RESEARCH       ADAMS             20        20
RESEARCH       FORD              20        20
RESEARCH       JONES             20        20
RESEARCH       SCOTT             20        20
RESEARCH       SMITH             20        20
SALES          ALLEN             30        30
SALES          BLAKE             30        30
SALES          JAMES             30        30
SALES          MARTIN            30        30
SALES          TURNER            30        30
SALES          WARD              30        30
---------------------------------------------

[左连接：如下图，假如出现条件不符和的，以右边为主/d.deptno/,左边的/e.deptno/应该以空行还填补右边显示的内容]
select d.dname D_Dname,e.ename E_Ename,d.deptno D_Deptno,e.deptno E_Deptno from emp e,dept d
where e.deptno(+)=d.deptno order by d.dname,e.ename

D_DNAME
       E_ENAME     D_DEPTNO E_DEPTNO
-------------- ---------- --------- ---------
ACCOUNTING     CLARK             10        10
ACCOUNTING     KING              10        10
ACCOUNTING     MILLER            10        10
OPERATIONS                       40
RESEARCH       ADAMS             20        20
RESEARCH       FORD              20        20
RESEARCH       JONES             20        20
RESEARCH       SCOTT             20        20
RESEARCH       SMITH             20        20
SALES          ALLEN             30        30
SALES          BLAKE             30        30
SALES          JAMES             30        30
SALES          MARTIN            30        30
SALES          TURNER            30        30
SALES          WARD              30        30
---------------------------------------------
[自连接：同一表表根据别名来访问]
select a.ename A_ename,b.ename B_ename,a.mgr A_mgr,b.empno B_empno
from emp a,emp b
where a.mgr=b.empno
order by b.ename,a.ename

A_ENAME
   B_ENAME        A_MGR   B_EMPNO
---------- ---------- --------- ---------
ALLEN      BLAKE           7698      7698
JAMES      BLAKE           7698      7698
MARTIN     BLAKE           7698      7698
TURNER     BLAKE           7698      7698
WARD       BLAKE           7698      7698
MILLER     CLARK           7782      7782
SMITH      FORD            7902      7902
FORD       JONES           7566      7566
SCOTT      JONES           7566      7566
BLAKE      KING            7839      7839
CLARK      KING            7839      7839
JONES      KING            7839      7839
ADAMS      SCOTT           7788      7788
-----------------------------------------
select e.deptno,e.ename from emp e
where exists
(select 'x' from dept d where e.deptno=d.deptno
and d.loc='NEW YORK')
order by e.empno;

   DEPTNO ENAME
--------- ----------
       10 CLARK
       10 KING
       10 MILLER