第一課：客戶端

1. Sql Plus(客戶端），命令行直接輸入：sqlplus，然后按提示輸入用戶名，密碼。

2. 從開始程序運(yùn)行:sqlplus，是圖形版的sqlplus.

3. http://localhost:5560/isqlplus

第二課：更改用戶

1. sqlplus sys/bjsxt as sysdba

2. alter user scott account unlock;(解鎖)

第三課：table structure

1. 描述某一張表：desc 表名:desc emp 、desc dept 、desc salgrade

2. select * from 表名

第四課：select 語句：

1.計(jì)算數(shù)據(jù)可以用空表：比如：.select 2*3 from dual

2.select ename,sal*12 annual_sal from emp;與select ename,sal*12 "annual sal" from emp;區(qū)別，別名不要用"_"連接起來，同時(shí)加了雙引號可以保持住原來的格式。

3. select ename || ‘a(chǎn)bcd’。如果連接字符串中含有單引號，用兩個(gè)單引號代替一個(gè)單引號；“||”相當(dāng)于java中的“+”

4.select sysdate from dual;顯示當(dāng)前時(shí)間

第五課：distinct

select deptno from emp;

select distinct deptno from emp;

select distinct deptno from emp;

select distinct deptno ,job from emp

去掉deptno,job兩者組合的重復(fù)。更多的項(xiàng)，就是這么多項(xiàng)的組合的不重復(fù)組合。

第六課：Where

select * from emp where deptno =10;

select * from emp where deptno <> 10;不等于10

select * from emp where ename ='bike';

select ename,sal from emp where sal between 800 and 1500 (>=800 and <=1500)

空值處理:

select ename,sal,comm from emp where comm is (not) null;

select ename,sal,comm from emp where ename ( not)in ('smith','king','abc');

select ename from emp where ename like '_A%';_代表一個(gè)字母,%代表0個(gè)或多個(gè)字母. 如果查詢%

可用轉(zhuǎn)義字符.\%. 還可以用escape '$'比如:select ename from emp where ename like '%$a%' escape '$';

第七課: order by

select * from dept;

select * from dept order by dept desc;(默認(rèn):asc)

select ename,sal,deptno from emp order by deptno asc,ename desc;先按照deptno升序，如果數(shù)據(jù)相同則按照ename降序

第八課: sql function1:

select ename,sal*12 annual_sal from emp

where ename not like '_A%' and sal>800

order by sal desc;

select lower(ename) from emp;

select ename from emp

where lower(ename) like '_a%';等同于

select ename from emp where ename like '_a%' or ename like '_A%';

select substr(ename,2,3) from emp;從第二字符截,一共截三個(gè)字符.

select chr(65) from dual 結(jié)果為:A

select ascii('A') from dual 結(jié)果為:65

select round(23.652,1) from dual; 結(jié)果為: 23.7

select round(23.652,-1) from dual;20 四舍五入到十位數(shù)

select to_char(sal,'$99_999_999') from emp;//'$99_999_999'是指定的格式，9代表一位數(shù)字

select to_char(sal,'L99_999_999') from emp;人民幣符號,L:代表本地符號

這個(gè)需要掌握牢:

select birthdate from emp;

顯示為:

BIRTHDATE

----------------

17-12月-80

----------------

改為:

select to_char(birthdate,'YYYY-MM-DD HH:MI:SS') from emp;

顯示:

BIRTHDATE

-------------------

1980-12-17 12:00:00

-------------------

select to_char(sysdate,'YYYY-MM-DD HH24:MI:SS') from dual; //也可以改為:HH12

TO_CHAR(SYSDATE,'YY

-------------------

2007-02-25 14:46:14

to_date函數(shù):

select ename,birthdate from emp where birthdate > to_date('1981-2-20 12:34:56','YYYY-MM-DD HH24:MI:SS');

如果直接寫 birthdate>'1981-2-20 12:34:56'會出現(xiàn)格式不匹配,因?yàn)楸碇械母袷綖? DD-MM月-YY.

select sal from emp where sal>888.88 無錯(cuò).但

select sal from emp where sal>$1,250,00;

會出現(xiàn)無效字符錯(cuò)誤.

改為:

select sal from emp where sal>to_number('$1.250.00','$9,999,99');

把空值改為0

select ename,sal*12+nvl(comm,0) from emp;

這樣可以防止comm為空時(shí),sal*12相加也為空的情況.

第九課: Group function 組函數(shù)

max,min,avg ,count,sum函數(shù)

select to_char(avg(sal),'99999999,99') from emp;

select round(avg(sal),2) from emp;

結(jié)果:2073.21

select count(*) from emp where deptno=10;

select count(ename) from emp where deptno=10; count某個(gè)字段,如果這個(gè)字段不為空就算一個(gè).

select count(distinct deptno) from emp;

select sum(sal) from emp;

第十課: Group by語句

需求:現(xiàn)在想求,求每個(gè)部門的平均薪水.

select avg(sal) from emp group by deptno;

select deptno,avg(sal) from emp group by deptno;

select deptno,job,max(sal) from emp group by deptno,job;

求薪水值最高的人的名字.

select ename,max(sal) from emp;出錯(cuò),因?yàn)閙ax只有一個(gè)值,但等于max值的人可能好幾個(gè),不能匹配.

應(yīng)如下求:

select ename from emp where sal=(select max(sal) from emp);

Group by語句應(yīng)注意,

出現(xiàn)在select中的字段,如果沒出現(xiàn)在組函數(shù)中,必須出現(xiàn)在Group by語句中.

第十一課: Having 對分組結(jié)果篩選

Where是對單條紀(jì)錄進(jìn)行篩選,Having是對分組結(jié)果進(jìn)行篩選.

select avg(sal),deptno from emp

group by deptno

having avg(sal)>2000;

查詢工資大于1200雇員,按部門編號進(jìn)行分組,分組后平均薪水大于1500,按工薪倒充排列.

select * from emp

where sal>1200

group by deptno

having avg(sal)>1500

order by avg(sal) desc;

第十二課:子查詢

誰掙的錢最多(誰:這個(gè)人的名字, 錢最多)

select 語句中嵌套select 語句,可以在where,from后.

問那些人工資,在平均工資之上.

select ename,sal from emp where sal>(select avg(sal) from emp);

查找每個(gè)部門掙錢最多的那個(gè)人的名字.

select ename ,deptno from emp where sal in(select max(sal) from ename group by deptno) 查詢會多值.

應(yīng)該如下:

select max(sal),deptno from emp group by deptno;當(dāng)成一個(gè)表.語句如下:

select ename, sal from emp join(select max(sal) max_sal,deptno from emp group

by deptno) t on(emp.sal=t.max_sal and emp.deptno=t.deptno);

每個(gè)部門的平均薪水的等級.

分析:首先求平均薪水(當(dāng)成表),把平均薪水和另外一張表連接.

第十四課:self_table_connection(自連接)：給同一個(gè)表取相同的別名

把某個(gè)人的名字以及他的經(jīng)理人的名字求出來(經(jīng)理人及這個(gè)人在表中同處一行)

分析:首先求出這個(gè)人的名字,取他的編號,然后從另一張表與其相對應(yīng)編號,然后找到經(jīng)理的名字.

select e1.ename ,e2.ename from emp e1,emp e2 where e1.mgr= e2.empno.

empno編號和MGR都是編號.

第十15課: SQL1999_table_connections

select ename,dname,grade from emp e,dept d, sqlgrade s

where e.deptno = d.deptno and e.sql between s.losal and s.hisal and

job<>'CLERK';

有沒有辦法把過濾條件和連接條件分開來? 出于這樣考慮,Sql1999標(biāo)準(zhǔn)推出來了.有許多人用的還是

舊的語法,所以得看懂這種語句.

select ename,dname from emp,dept;(舊標(biāo)準(zhǔn)).

select ename,dname from emp cross join dept;(1999標(biāo)準(zhǔn))

select ename,dname from emp,dept where emp.deptno=dept.deptno (舊)

select ename,dname from emp join dept on(emp.deptno = dept.deptno); 1999標(biāo)準(zhǔn).沒有Where語句.

select ename,dname from emp join dept using(deptno);等同上句,但不推薦使用.

select ename,grade from emp e join salgrade s on(e.sal between s.losal and s.hisal);

join 連接語句, on過濾條件。連接，條件一眼分開。如果用Where語句較長時(shí)，連接語句和過濾語句混在一起。

三張表連接：

slect ename,dname, grade from

emp e join dept d on(e.deptno=d.deptno)

join salgrade s on(e.sal between s.losal and s.hisal)

where ename not like '_A%';

把每張表連接 條件不混在一起，然后數(shù)據(jù)過濾條件全部區(qū)分開來。讀起來更清晰，更容易懂一點(diǎn)。

select e1.ename,e2.ename from emp e1 join emp e2 on(e1.mgr = e2.emptno);

左外連接：會把左邊這張表多余數(shù)據(jù)顯示出來。

select e1.ename,e2,ename from emp e1 left join emp e2 on(e1.mgr =e2.empno);left 后可加outer

右外連接：

select ename,dname from emp e right outer join dept d on(e.deptno =d.deptno); outer可以取掉。

即把左邊多余數(shù)據(jù)，也把右邊多余數(shù)據(jù)拿出來，全外連接。

select ename,dname from emp e full join dept d on(e.deptno =d.deptno);

16-23 課：求部門平均薪水的等級

A.求部門平均薪水的等級。

select deptno,avg_sal,grade from

(select deptno,avg(sal) avg_sal from emp group by deptno)t

join salgrade s on(t.avg_sal between s.losal and s.hisal)

B.求部門平均的薪水等級

select deptno,avg(grade) from

(select deptno,ename, grade from emp join salgrade s on(emp.sal between s.losal and

s.hisal)) t

group by deptno

C.哪些人是經(jīng)理

select ename from emp where empno in(select mgr from emp);

select ename from emp where empno in(select distinct mgr from emp);

D.不準(zhǔn)用組函數(shù)，求薪水的最高值（面試題）

select distinct sal from emp where sal not in(

select distinct e1.sal from emp e1 join emp e2 on (e1.sal<e2.sal));

E.平均薪水最高的部門編號

select deptno,avg_sal from

(select avg(sal)avg_sal,deptno from emp group by deptno)

where avg_sal=

(select max(avg_sal)from

(select avg(sal) avg_sal,deptno from emp group by deptno)

)

F.平均薪水最高的部門名稱

select dname from dept where deptno=

(

select deptno from

(select avg(sal)avg_sal,deptno from emp group by deptno)

where avg_sal=

(select max(avg_sal)from

(select avg(sal) avg_sal,deptno from emp group by deptno)

)

)

G.求平均薪水的等級最低的部門的部門名稱

組函數(shù)嵌套

如：平均薪水最高的部門編號，可以E.更簡單的方法如下：

select deptno,avg_sal from

(select avg(sal) avg_sal,deptno from emp group by deptno)

where avg_sal =

(select max(avg(sal)) from emp group by deptno)

組函數(shù)最多嵌套兩層

分析：

首先求

1.平均薪水： select avg(sal) from group by deptno;

2.平均薪水等級： 把平均薪水當(dāng)做一張表，需要和另外一張表連接salgrade

select deptno,grade avg_sal from

( select deptno,avg(sal) avg_sal from emp group by deptno) t

join salgrade s on(t.avg_sal between s.losal and s.hisal)

上面結(jié)果又可當(dāng)成一張表。

DEPTNO GRADE AVG_SAL

-------- ------- ----------

30 3 1566.66667

20 4 2175

10 4 2916.66667

3.求上表平均等級最低值

select min(grade) from

(

select deptno,grade,avg_sal from

(select deptno,avg(sal) avg_sal from emp group by deptno)t

join salgrade s on(t.avg_sal between s.losal and s.hisa)

)

4.把最低值對應(yīng)的2結(jié)果的那張表的對應(yīng)那張表的deptno, 然后把2對應(yīng)的表和另外一張表做連接。

select dname ,deptno,grade,avg_sal from

(

? select deptno,grade,avg_sal from

(select deptno,avg(sal) avg_sal from emp group by deptno)t

join salgrade s on(t.avg_sal between s.losal and s.hisal)

) t1

join dept on (t1.deptno = dept.deptno)

where t1.grade =

(

select deptno,grade,avg_sal from

(select deptno,avg(sal) avg_sal from emp group by deptno) t

join salgrade s on(t.avg_sal between s.losal and s.hisal)

)

)

結(jié)果如下：

DNAME DEPTNO GRADE AVG_SAL

-------- ------- -------- --------

SALES 30 3 1566.6667

H: 視圖（視圖就是一張表，一個(gè)字查詢）

G中語句有重復(fù)，可以用視圖來簡化。

conn sys/bjsxt as sysdba;

grant create table,create view to scott;

conn scott/tiger

創(chuàng)建視圖：

create view v$_dept_avg-sal_info as

select deptno,grade,avg_sal from

( select deptno,avg(sal) avg_sal from emp group by deptno)t

join salgrade s on 9t.avg_sal between s.losal and s.hisal)

然后

select * from v$_dept_avg-sal_info

結(jié)果如下：

DEPTNO GRADE AVG_SAL

-------- ------- ----------

30 3 1566.66667

20 4 2175

10 4 2916.66667

然后G中查詢可以簡化成：

select dname,t1.deptno,grade,avg_sal from

v$_dept_avg-sal_info t1

join dept on9t1.deptno =dept.deptno)

where t1.grade=

(

select min(grade) from v$_dept_avg-sal_info t1

)

創(chuàng)建新用戶：

1.backup scott

exp

2.create user

1)Create user fanjiabin identified by fanjiabin default tablespace users quota 10M on users

2)grant create session,cteate table,cteate view to fanjiabin

3.import the data

imp

--變量聲明，使用%type屬性

declare

v_empno number(4);

v_empno2 emp.empno%type;

v_empno3 v_empno2%type;

begin

dbms_output.put_line('test');

end;

--table變量類型(數(shù)組)

declare

type type_table_emp_empno is table of emp.empno%type index by binary_integer;

v_empnos type_table_emp_empno;

begin

v_empnos(0) := 7369;

v_empnos(2) := 7839;

v_empnos(-1) := 9999;

dbms_output.put_line(v_empnos(-1));

end;

--record變量類型（近似java中的類）

declare

type type_record_dept is record

(

deptno dept.deptno%type,

dname dept.dname%type,

loc dept.loc%type

);

v_temp type_record_dept;

begin

v_temp.deptno := 50;

v_temp.dname := 'aaa';

v_temp.loc := 'bj';

dbms_output.put_line(v_temp.deptno || ' ' || v_temp.dname);

end;

--使用%rowtype聲明record變量

declare

v_temp dept%rowtype;

begin

v_temp.deptno := 50;

v_temp.dname := 'aaa';

v_temp.loc := 'bj';

dbms_output.put_line(v_temp.deptno || ' ' || v_temp.dname);

end;

--SQL語句的運(yùn)用

--select語句

declare

v_name emp.ename%type;

v_sal emp.sal%type;

begin

select ename, sal into v_name, v_sal from emp where empno = 7369;

dbms_output.put_line(v_name || ' ' || v_sal);

end;

declare

v_emp emp%rowtype;

begin

select * into v_emp from emp where empno = 7369;

dbms_output.put_line(v_emp.ename);

end;

--insert語句

declare

v_deptno dept.deptno%type := 50;

v_dname dept.dname%type := 'aaa';

v_loc dept.loc%type := 'bj';

begin

insert into dept2 values(v_deptno, v_dname, v_loc);

commit;

end;

declare

v_deptno emp2.deptno%type := 10;

v_count number;

begin

--update emp2 set sal = sal/2 where deptno = v_deptno;

--select deptno into v_deptno from emp2 where empno = 7369;

select count(*) into v_count from emp2;

dbms_output.put_line(sql%rowcount || '條記錄被影響');

commit;

end;

DDL語句

begin

execute immediate 'create table t (nnn varchar2(20) default ''aaa'')';

end;

--if語句

取出7369的薪水，如果<1200，輸出'low'，如果<2000輸出'middle'，否則'high'

declare

v_sal emp.sal%type;

begin

select sal into v_sal from emp

where empno = 7369;

if (v_sal < 1200) then

dbms_output.put_line('low');

elsif (v_sal < 2000) then

dbms_output.put_line('middle');

else

dbms_output.put_line('high');

end if;

end;

--練習(xí)

--循環(huán)

declare

i binary_integer := 1;

begin

loop

dbms_output.put_line(i);

i := i + 1;

exit when (i >= 11);

end loop;

end;

---------

declare

j binary_integer := 1;

begin

while j < 11 loop

dbms_output.put_line(j);

j := j + 1;

end loop;

end;

-----------

begin

for k in 1..10 loop

dbms_output.put_line(k);

end loop;

for k in reverse 1..10 loop

dbms_output.put_line(k);

end loop;

end;

--錯(cuò)誤處理

declare

v_temp number(4);

begin

select empno into v_temp from emp where empno = 10;

exception

when too_many_rows then

dbms_output.put_line('太多紀(jì)錄了');

when others then

dbms_output.put_line('error');

end;

----------

declare

v_temp number(4);

begin

select empno into v_temp from emp where empno = 2222;

exception

when no_data_found then

dbms_output.put_line('沒有數(shù)據(jù)');

end;

---------

--創(chuàng)建事件日志表

create table errorlog

(

id number primary key,

errcode number,

errmsg varchar2(1024),

errdate date

)

--創(chuàng)建序列

create sequence seq_errorlog_id start with 1 increment by 1

--實(shí)驗(yàn)

declare

v_deptno dept.deptno%type := 10;

v_errcode number;

v_errmsg varchar2(1024);

begin

delete from dept where deptno = v_deptno;

commit;

exception

when others then

rollback;

v_errcode := SQLCODE;

v_errmsg := SQLERRM;

insert into errorlog values (seq_errorlog_id.nextval, v_errcode, v_errmsg, sysdate);

commit;

end;

--游標(biāo)

declare

cursor c is

select * from emp;

v_temp c%rowtype;

begin

open c;

fetch c into v_temp;

dbms_output.put_line(v_temp.ename);

close c;

end;

------------------

declare

cursor c is

select * from emp;

v_emp c%rowtype;

begin

open c;

loop

fetch c into v_emp;

exit when (c%notfound);

dbms_output.put_line(v_emp.ename);

end loop;

close c;

end;

----------------------

declare

cursor c is

select * from emp;

v_emp c%rowtype;

begin

open c;

fetch c into v_emp;

while (c%found) loop

dbms_output.put_line(v_emp.ename);

fetch c into v_emp;

end loop;

close c;

end;

-----------------

declare

cursor c is

select * from emp;

begin

for v_emp in c loop

dbms_output.put_line(v_emp.ename);

end loop;

end;

--帶參數(shù)的游標(biāo)

declare

cursor c (v_deptno emp.deptno%type, v_job emp.job%type)

is

select ename, sal from emp where deptno = v_deptno and job = v_job;

begin

for v_temp in c(30,'CLERK') loop

dbms_output.put_line(v_temp.ename);

end loop;

end;

--可更新的游標(biāo)

declare

cursor c

is

select * from emp2 for update;

begin

for v_temp in c loop

if (v_temp.sal < 2000) then

update emp2 set sal = sal * 2 where current of c;

elsif (v_temp.sal = 5000) then

delete from emp2 where current of c;

end if;

end loop;

commit;

end;

----------------

--存儲過程

create or replace procedure p

is

cursor c

is

select * from emp2 for update;

begin

for v_temp in c loop

if (v_temp.deptno = 10) then

update emp2 set sal = sal + 10 where current of c;

elsif (v_temp.deptno = 20) then

update emp2 set sal = sal + 20 where current of c;

else

update emp2 set sal = sal + 50 where current of c;

end if;

end loop;

commit;

end;

--執(zhí)行

exec p;

或

begin;

p;

end;

--帶參數(shù)的存儲過程

create or replace procedure p

(v_a in number, v_b number, v_ret out number, v_temp in out number)

is

begin

if (v_a > v_b) then

v_ret := v_a;

else

v_ret := v_b;

end if;

v_temp := v_temp + 1;

end;

--實(shí)驗(yàn)

declare

v_a number := 3;

v_b number := 4;

v_ret number;

v_temp number := 5;

begin

p(v_a, v_b, v_ret, v_temp);

dbms_output.put_line(v_ret);

dbms_output.put_line(v_temp);

end;

-------------------

--函數(shù)

create or replace function sal_tax

(v_sal number)

return number

is

begin

if (v_sal < 2000) then

return 0.10;

elsif (v_sal < 2750) then

return 0.15;

else

return 0.20;

end if;

end；

--觸發(fā)器

create table emp2_log

(

uname varchar2(20),

action varchar(10),

atime date

)

-----------

create or replace trigger trig

after insert or update or delete on emp2

begin

if inserting then

insert into emp2_log values (USER, 'insert', sysdate);

elsif updating then

insert into emp2_log values (USER, 'update', sysdate);

elsif deleting then

insert into emp2_log values (USER, 'delete', sysdate);

end if;

end;

----------

update emp2 set sal = sal * 2 where deptno = 30;

--------

create or replace trigger trig

after insert or update or delete on emp2 for each row

begin

if inserting then

insert into emp2_log values (USER, 'insert', sysdate);

elsif updating then

insert into emp2_log values (USER, 'update', sysdate);

elsif deleting then

insert into emp2_log values (USER, 'delete', sysdate);

end if;

end;

-------------

--不提倡使用

create or replace trigger trig

after update on dept for each row

begin

update emp2 set deptno = :NEW.deptno where deptno = :OLD.deptno;

end;

----------------------

--樹狀結(jié)構(gòu)的存儲與展現(xiàn)

drop table article;

create table article

(

id number primary key,

cont varchar2(4000),

pid number,

isleaf number(1), --0代表非葉子節(jié)點(diǎn)，1代表葉子節(jié)點(diǎn)

alevel number(2)

)

-------------

insert into article values (1, '螞蟻大戰(zhàn)大象', 0, 0, 0);

insert into article values (2, '大象被打趴下了', 1, 0, 1);

insert into article values (3, '螞蟻也不好過', 2, 1, 2);

insert into article values (4, '瞎說', 2, 0, 2);

insert into article values (5, '沒有瞎說', 4, 1, 3);

insert into article values (6, '怎么可能', 1, 0, 1);

insert into article values (7, '怎么沒可能', 6, 1, 2);

insert into article values (8, '可能性是很大的', 6, 1, 2);

insert into article values (9, '大象進(jìn)醫(yī)院了', 2, 0, 2);

insert into article values (10, '護(hù)士是螞蟻', 9, 1, 3);

commit;

---------

螞蟻大戰(zhàn)大象

大象被打趴下了

螞蟻也不好過

瞎說

沒有瞎說

大象進(jìn)醫(yī)院了

護(hù)士是螞蟻

怎么可能

怎么不可能

可能性是很大的

--------------------------

create or replace procedure p (v_pid article.pid%type, v_level binary_integer) is

cursor c is select * from article where pid = v_pid;

v_preStr varchar2(1024) := '';

begin

for i in 1..v_level loop

v_preStr := v_preStr || '****';

end loop;

for v_article in c loop

dbms_output.put_line(v_preStr || v_article.cont);

if (v_article.isleaf = 0)

then

p (v_article.id, v_level + 1);

end if;

end loop;

end;

總結(jié)

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