收录的一些常用的SQL语句，也许你能用上
收录的一些基础的SQl语句，有些用处，平时用的。
创建某一个表：
CREATE TABLE [weekyc] (
[yc_product] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NULL ,
[yc_max] [numeric](18, 0) NULL ,
[yc_min] [numeric](18, 0) NULL ,
[yc_situation] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NULL ,
[yc_time] [datetime] NULL ,
[id] [numeric](18, 0) IDENTITY (1, 1) NOT NULL ,
[Authority] [int] NOT NULL CONSTRAINT [DF_weekyc_Authority] DEFAULT (3),
[remark] [nvarchar] (50) COLLATE Chinese_PRC_CI_AS NULL
) ON [PRIMARY]
GO
修改某一个表：
alter table weekyc add yc_max numeric(18,0) null
ALTER TABLE [weekyc] ADD DEFAULT '0' FOR [yc_max]
删除一个约束:
declare @name varchar(8000)
select @name=b.name from syscolumns a,sysobjects b where a.id=object_id('weekyc') and b.id=a.cdefault and
a.name='yc_max' and b.name like 'DF%'
exec('alter table weekyc drop constraint '+@name)
if not exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[tablespaceinfo]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
create table tablespaceinfo --创建结果存储表
(nameinfo varchar(50) ,
rowsinfo int , reserved varchar(20) ,
datainfo varchar(20) ,
index_size varchar(20) ,
unused varchar(20) )
delete from tablespaceinfo --清空数据表
declare @tablename varchar(255) --表名称
declare @cmdsql varchar(500)
DECLARE Info_cursor CURSOR FOR
select o.name
from dbo.sysobjects o where OBJECTPROPERTY(o.id, N'IsTable') = 1
and o.name not like N'#%%' order by o.name
OPEN Info_cursor
FETCH NEXT FROM Info_cursor
INTO @tablename
WHILE @@FETCH_STATUS = 0
BEGIN
if exists (select * from dbo.sysobjects where id = object_id(@tablename) and OBJECTPROPERTY(id, N'IsUserTable') = 1)
execute sp_executesql
N'insert into tablespaceinfo exec sp_spaceused @tbname',
N'@tbname varchar(255)',
@tbname = @tablename
FETCH NEXT FROM Info_cursor
INTO @tablename
END
CLOSE Info_cursor
DEALLOCATE Info_cursor
GO
数据库执行进程：sp_cmdshell
查询/修改/删除中影响的列：
RowCount
删除表中的重复数据：
（假设ID是Identity列，Title相同者将被删除）
delete from TableName where id not in(select max(id) from TableName group by Title)
查看表信息：
select * from tablespaceinfo
清空数据库：
truncate table XX;
查看某库下面每个表占用的空间信息：
use XXDB;
select object_name(id) tablename,8*reserved/1024 reserved,rtrim(8*dpages/1024)+'Mb' used,8*(reserved-dpages)/1024 unused,8*dpages/1024-rows/1024*minlen/1024 free,
rows,* from sysindexes
where indid=1
order by reserved desc
sp_helptext XX;这是查看源码。
查看数据库进程sp_who;或者sp_who2更加详细;
绑定默认值 sp_binddefault xx;或者alter table xx add default xx for 列；
修改数据库名称，修改表名称，修改存储过程名称，修改视图名称：sp_rename 老的名字,新的名字
一个比较复杂的：DBCC，具体怎么用，太多了。
删除SQL日志：
dump transaction databasename with no_log and truncate_only
关键词：数据库,SQL,语句
