--DDL,DML
create table student(
name varchar(20),
age number(3)
)
insert into student values('Tom',18)
drop table student
delete from student where age =20
--varchar 可以存储空字符串但是varchar2存储空字符串为null；
create table person(
name varchar2(20)
age number(3)
)
insert into person values('Tom');
drop table peson
delete from student where age =20;
----------------------------------------------------------
hibernate5 struts2 spring4
---------------------------------------------------
--更新数据 左闭右开
update student set adress = trunc(dbm_random.value(1,4)) where adress is null;
update student set adress = null;
update student set adress = '01';
where adress = '1'
--增加列
alert table add (telephone varchar2(16))
--注释
comment on column student.telephone is '01 市电话 02 县电话 03 所电话'
--字符函数
Select substr(’abcdefg’,1,3) substr,
Instr(‘abcdefg’,’c’) instr,
‘hello’ || ‘world’ concate
From table1
--数字函数
Select to_number(‘01234’) number1,
Trunc(to_number(‘0123.678’),2) number2,
To_number(1000,’xxxx’) number3
From table1
--distinct函数
Select count(distinct equiptype) from tables
Select count(1) from table1
--interval日期加减 next_day()函数
Select to_char(faulttime – interval ‘7’ month, ‘yyyy-mm-dd hh24:mi:ss’) intervalyear
From table1
Select faulttime today,next_day(faulttime,6) nextday from table1
--decode==case when 函数
Selct decode(position, ‘01’,’平原’，’02’,’林区’,’03’,’山区’) position
From table1
--存储过程语法
Create or replace procedure SP_Updata_Age
(
uName in varchar,
Age int age
)
As
Begin
Update student set UserAge = UserAge + Age where username = uname
--commit
End SP_Updata_Age
--执行
Exec SP_Updata_Age(‘jack’,1)