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為偽列]
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;
[列別名]
select e.ename EMPLOYEE,e.sal*1.15 NEW_SAl from emp e where e.deptno=10;
[多表串連]
select d.dname,e.ename,e.sal,e.comm from emp e,dept d where d.deptno=e.deptno order by d.deptno;
[使用子查詢]
select ename from emp where deptno=(select deptno from dept where dname='SALES');
[查詢別名]
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:聯合]
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)
---------------------
數值函數
abs(number)
ceil(number)
cos(number)
ln(number)
mod(n,m)
round(number,decimal_digits)
sign(number)
sqrt(number)
sin(number)
-------------------
字元函數
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
---------------------------------------------------------------------------
[右串連：如下圖，如果出現條件不符和的，以左邊為主/e.deptno/,右邊的/d.deptno/應該以空行還填補左邊顯示的內容]
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
---------------------------------------------
[左串連：如下圖，如果出現條件不符和的，以右邊為主/d.deptno/,左邊的/e.deptno/應該以空行還填補右邊顯示的內容]
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
---------------------------------------------
[自串連：同一表表根據別名來訪問]
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
