create table pet(
pno number (10),
pname varchar2(20),
sex varchar2(2)
)
drop table pet
alter table pet modify pno number(10,2)
alter table pet add ptype vachar2(20)
alter table pet drop column sex
create table stu(
sName varchar2(10),
sNum number(10),
sMajor varchar2(20),
sAge number(3)
)
drop table stu
alter table stu add sAge number(3)
alter table stu drop column sDate
insert into tablename(列名1,列名2...)values(列1,列2...)
begin
insert into stu(sname,snum,smajor,sage)
values ('小左',20434365,'计算机',2);
insert into stu(sname,snum,smajor,sage)
values ('小右',20434366,'计算机',20);
commit;
end;
delete from tablename 【where tableYS = "查询关键字"】
delete from stu where sname = '小左'
update tablename set tableYS1 = "更改内容" where tableYS2 = "查询关键字"
update stu set sAge = 19 where sname = '小左'
select *【查询全部列; 可写列名1,列名2;运算显示{nvl(YS,0):为0的实际为null,此函数转为0}】 from tablename
select * from stu
select snum,sage from stu
select sage*2 from stu
select 'name:'||sname as 姓名||'age='||sage as 年龄 from stu
select * tablename where"查询条件(组合条件and,or同时用时and优先级高)"
select * from stu where sage > 5 and sage <25
create table myt(
username varchar2(10),
address varchar2(30),
salary number(8),
departmenname varchar2(15)
)
begin
insert into myt(username,address,salary,departmenname)
values ('张三','哈尔滨',6000,'事业部');
insert into myt(username,address,salary,departmenname)
values ('李四','北京',8000,'事业部');
insert into myt(username,address,salary,departmenname)
values ('张武','大连',5000,'产业部');
insert into myt(username,address,salary,departmenname)
values ('张三丰','重庆',4000,'工业部');
insert into myt(username,address,salary,departmenname)
values ('张三丰','重庆',4000,'食堂部');
insert into myt(username,address,salary,departmenname)
values ('刘德华','上海',7000,'哈哈部');
commit;
end;
select username,address,salary from myt
select username,address,salary*12+1200 from myt
select username,address,salary*12+1000 from myt
select address,username,salary from myt where departmenname = '事业部'
select username,'居住于'||address as 居住地,salary from myt where departmenname = '事业部'
select username as 姓名,address as 居住地,salary as 月薪,salary*12 as 年薪 from myt
select username as "姓 名",address as "居 住 地",salary as "月 薪",salary*12 as "年 薪" from myt
select * from myt where salary = 6000
select * from myt where salary between 6000 and 8000
select * from myt where salary in(6000,7000,8000)
select * from myt where username like '张%' and salary between 6000 and 8000
select * from myt where salary in(6000,7000,8000) and username like '张%' and username !='张三丰'
select * from myt where salary = 5000 or username = '张三'
select * from myt order by salary
select * from myt order by salary*12
select * from myt order by salary desc