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，如果出现条件不符和的，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，如果出现条件不符和的，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