SQL语句先前写的时候,很容易把一些特殊的用法忘记,我特此整理了一下SQL语句操作。 ;Q} H'Wg,
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一、基础 8cyC\Rs
1、说明:创建数据库 0ge^pO\Z
CREATE DATABASE database-name d8Kxtg
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2、说明:删除数据库 =C.WM*= '
drop database dbname =3Hv
3、说明:备份sql server Um'r6ty
--- 创建 备份数据的 device 9K`uGu
USE master !~~j&+hK\
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' gC qQ~lWZ
--- 开始 备份 Jf=$h20x
BACKUP DATABASE pubs TO testBack CuD ^@
4、说明:创建新表 $1$T2'C~+
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) #yVMC;J?W
根据已有的表创建新表: &BDdJwE
A:create table tab_new like tab_old (使用旧表创建新表) 2r|!:^'?W
B:create table tab_new as select col1,col2... from tab_old definition only wk"zpI7L
5、说明:删除新表 ]/{987
drop table tabname .}l&lj@#
6、说明:增加一个列 y3vm+tJc{
Alter table tabname add column col type ^9C9[$Q
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。 \v}3j^Yu
7、说明:添加主键: Alter table tabname add primary key(col) 19t'
说明:删除主键: Alter table tabname drop primary key(col) {b6g!sE
8、说明:创建索引:create [unique] index idxname on tabname(col....) vz_ZXy9Z
删除索引:drop index idxname kbkq.fYr
注:索引是不可更改的,想更改必须删除重新建。 |r=.}9
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9、说明:创建视图:create view viewname as select statement ib%x&?||
删除视图:drop view viewname \7Fkeo+
10、说明:几个简单的基本的sql语句 E5b JIC(
选择:select * from table1 where 范围 p-t*?p
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插入:insert into table1(field1,field2) values(value1,value2) +2+wNFU
删除:delete from table1 where 范围 .4NQ2k1io
更新:update table1 set field1=value1 where 范围 op%?V:
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! .5~W3v
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排序:select * from table1 order by field1,field2 [desc] dnP3{!"b
总数:select count as totalcount from table1 on q~wEr
求和:select sum(field1) as sumvalue from table1 ?w[M{
平均:select avg(field1) as avgvalue from table1 YQ+Kl[ec
最大:select max(field1) as maxvalue from table1 4{r_EV[(
最小:select min(field1) as minvalue from table1 @GiR~bKZ
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