oracle数据库基本操作
1.初始orcle
. 练习所需表 以下纯代码都是此表操作
create table teacher2(
name varchar2(30),
tid number(4) primary key ,
monmary varchar2(100)
);
insert into teacher(name,tid,monmary) values('张三',01,'描述');
insert into teacher(name,tid,monmary) values('李四',02,'描述');
insert into teacher(name,tid,monmary) values('王二',03,'描述');
insert into teacher(name,tid,monmary) values('王五',04,'描述');
insert into teacher(name,tid,monmary) values('王六',05,'描述');
insert into teacher(name,tid,monmary) values('王琦',06,'描述');
insert into teacher(name,tid,monmary) values('网吧',07,'描述');
insert into teacher(name,tid,monmary) values('账务',08,'描述');
insert into teacher(name,tid,monmary) values('李六',09,'描述');
insert into teacher(name,tid,monmary) values('篱笆',10,'描述');
insert into teacher(name,tid,monmary) values('王下',11,'描述');
select * from teacher;
去重
select distinct monmary from teacher;
分页查询
select * from
(select name,rownum as rn from teacher) t
where rn between 5 and 10;
创建新表
create table teacher2
as
select * from teacher;
select * from teacher2;
集合函数
--union 相同列加不同列
select * from teacher
union
select * from teacher2;
--union all 全部列
select * from teacher
union all
select * from teacher2;
--intersect 相同列
select * from teacher
intersect
select * from teacher2;
--minus 不同列
select * from teacher
minus
select * from teacher2;
转换函数
--tochar
SELECT to_char(324,'$9,9,9,9,9') FROM dual;
--todate
SELECT SYSDATE FROM dual;
SELECT to_date('1999-01-01','yyyy-MM-dd') FROM dual;
if else
SELECT NVL(2,3)FROM dual;
SELECT NVL2(NULL,1,10)FROM dual;
--switch
SELECT DECODE(2,1,'一月',2,'二月','100')FROM dual;
分析函数
SELECT NAME,tid ,
RANK() OVER(PARTITION BY NAME ORDER BY tid DESC) "rank",
dense_RANK() OVER(PARTITION BY NAME ORDER BY tid DESC) "dense_RANK",
row_number() OVER(PARTITION BY NAME ORDER BY tid DESC) "row_number"
FROM teacher t;
2.orcle核心操作
1.表空间
--创建表空间
CREATE TABLESPACE tb_sbs
DATAFILE 'd:\orcleSpace\tb1.dbf'
SIZE 50m;
--更改表空间文件大小
ALTER DATABASE
DATAFILE 'd:\orcleSpace\tb1.dbf'
RESIZE 100m;
--为表空间添加数据库文件 ,并文件大小自动增长
ALTER TABLESPACE tb_sbs
ADD DATAFILE 'd:\orcleSpace\tb2.dbf'
SIZ