马士兵oracle视频教程笔记
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.計算數據可以用空表：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;區別，別名不要用"_"連接起來，同時加了雙引號可以保持住原來的格式。
3. select ename || ‘abcd’。如果連接字符串中含有單引號，用兩個單引號代替一個單引號；“||”相當于java中的“+”
4.select sysdate from dual;顯示當前時間
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。更多的項，就是這么多項的組合的不重復組合。
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%';_代表一個字母,%代表0個或多個字母. 如果查詢%
可用轉義字符.\%. 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:asc)
select ename,sal,deptno from emp order by deptno asc,ename desc;先按照deptno升序，如果數據相同則按照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,一共截三個字符.
select chr(65) from dual 結果為:A
select ascii('A') from dual 結果為:65
select round(23.652,1) from dual; 結果為: 23.7
select round(23.652,-1) from dual;20 四舍五入到十位數
select to_char(sal,'$99_999_999') from emp;//'$99_999_999'是指定的格式，9代表一位數字
select to_char(sal,'L99_999_999') from emp;人民幣符號,L:代表本地符號
這個需要掌握牢:
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:
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'會出現格式不匹配,因為表中的格式為: DD-MM月-YY.
select sal from emp where sal>888.88 無錯.但
select sal from emp where sal>$1,250,00;
會出現無效字符錯誤.
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,sal*12相加也為空的情況.
第九課: Group function 組函數
max,min,avg ,count,sum函數
select to_char(avg(sal),'99999999,99') from emp;
select round(avg(sal),2) from emp;
結果:2073.21
select count(*) from emp where deptno=10;
select count(ename) from emp where deptno=10; count某個字段,如果這個字段不為空就算一個.
select count(distinct deptno) from emp;
select sum(sal) from emp;
第十課: Group by語句
需求:現在想求,求每個部門的平均薪水.
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,因為max只有一個值,但等于max值的人可能好幾個,不能匹配.
應如下求:
select ename from emp where sal=(select max(sal) from emp);
Group by語句應注意,
出現在select中的字段,如果沒出現在組函數中,必須出現在Group by語句中.
第十一課: Having 對分組結果篩選
Where是對單條紀錄進行篩選,Having是對分組結果進行篩選.
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);
查找每個部門掙錢最多的那個人的名字.
select ename ,deptno from emp where sal in(select max(sal) from ename group by deptno) 查詢會多值.
應該如下:
select max(sal),deptno from emp group by deptno;當成一個表.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);
每個部門的平均薪水的等級.
分析:首先求平均薪水(當成表),把平均薪水和另外一張表連接.
第十四課:self_table_connection(自連接)：給同一個表取相同的別名
把某個人的名字以及他的經理人的名字求出來(經理人及這個人在表中同處一行)
分析:首先求出這個人的名字,取他的編號,然后從另一張表與其相對應編號,然后找到經理的名字.
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標準推出來了.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;(舊標準).
select ename,dname from emp cross join dept;(1999標準)
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標準.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，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，然后數據過濾條件全部區分開來。讀起來更清晰，更容易懂一點。
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據顯示出來。
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。
即把左邊多余數據，也把右邊多余數據拿出來，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.不準用組函數，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)
上面結果又可當成一張表。
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.把最低值對應的2結果的那張表的對應那張表的deptno, 然后把2對應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，一個字查詢）
G中語句有重復，可以用視圖來簡化。
conn sys/bjsxt as sysdba;
grant create table,create view to scott;
conn scott/tiger
創建視圖：
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
--循環
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('沒有數據');
end;
---------
--創建事件日志表
create table errorlog
(
id number primary key,
errcode number,
errmsg varchar2(1024),
errdate date
)
--創建序列
create sequence seq_errorlog_id start with 1 increment by 1
--實驗
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
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;
--帶參數的游標
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
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;
--執行
exec p;
或
begin;
p;
end;
--帶參數的存儲過程
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;
--實驗
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
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;
----------------------
--樹狀結構的存儲與展現
drop table article;
create table article
(
id number primary key,
cont varchar2(4000),
pid number,
isleaf number(1), --0代表非葉子節點，1代表葉子節點
alevel number(2)
)
-------------
insert into article values (1, '螞蟻大戰大象', 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, '大象進醫院了', 2, 0, 2);
insert into article values (10, '護士是螞蟻', 9, 1, 3);
commit;
---------
螞蟻大戰大象
大象被打趴下了
螞蟻也不好過
瞎說
沒有瞎說
大象進醫院了
護士是螞蟻
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
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