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前言
短暂面试故几家公司后,深刻认识到自己学习知识的不足,遂决心好好复习之前的Linux、SQL等内容。
正文
1.基础语句
CREATE DATABASE database-name
drop database dbname
3、说明:备份sql server
--- 创建 备份数据的 device
USE master
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat'
--- 开始 备份
BACKUP DATABASE pubs TO testBack
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..)
create table tab_new like tab_old (使用旧表创建新表)
create table tab_new as select col1,col2… from tab_old definition only
drop table tabname
Alter table tabname add column col type
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。
7、说明:添加主键:
Alter table tabname add primary key(col)
Alter table tabname drop primary key(col)
create [unique] index idxname on tabname(col….)
drop index idxname
注:索引是不可更改的,想更改必须删除重新建。
9、说明:创建视图:
create view viewname as select statement
drop view viewname
select * from table1 where 范围
insert into table1(field1,field2) values(value1,value2)
delete from table1 where 范围
update table1 set field1=value1 where 范围
select * from table1 where field1 like ’%value1%’
select * from table1 order by field1,field2 [desc]
select count as totalcount from table1
select sum(field1) as sumvalue from table1
select avg(field1) as avgvalue from table1
select max(field1) as maxvalue from table1
select min(field1) as minvalue from table1
13、对数据库进行操作:
分离数据库: sp_detach_db; 附加数据库:sp_attach_db 后接表明,附加需要完整的路径名
14.如何修改数据库的名称:
sp_renamedb 'old_name', 'new_name'