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if exists(select * from sysobjects where name='atzk')--ÅжÏÊÇ·ñ´æÔڴ˱í
drop table atzk
go
create table atzk
(
nid int identity(1,1) primary key,--nid×Ô¶¯±àºÅ£¬²¢ÉèΪÖ÷¼ü¡£
mytitle varchar(50) not null,--֪ͨµÄ±êÌâ¡£
mycontents varchar(200)--·¢²¼Í¨ÖªµÄÄÚÈÝ¡£
)
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Number£ºÊý×ÖÀàÐÍ
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Pls_integer£ºÕûÊýÐÍ£¬²úÉúÒç³öµÄ´íÎó
Binary_integer£ºÕûÊýÐÍ
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Long£º±ä³¤×Ö·û£¬×2GB
Date£ºÈÕÆÚÐÍ
Boolean£º²¼¶ûÐÍ
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1 ϵͳȨÏÞ£ºÊý¾Ý¿âÖеĶÔÏó£¬ ±í£¬´´½¨±í£¬É¾³ý±í
2 ¶ÔÏóȨÏÞ£º¶ÔÊý¾ÝµÄÔö¡¢É¾¡¢¸Ä¡¢²é¡ ......
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1.ÔÚ±íÖвåÈëеÄÁУº
alter table tablename
add city varchar£¨2£© default 'rr' //¸³Ä¬ÈÏÖµ
2.Ð޸ıíÖеÄÁУº
alter table tablename
modify city varchar£¨20£©
3.ɾ³ý±íÖеÄÁУº
alter t ......
select *
from
(select [id]=row_number() over (order by getdate()),
date=convert(varchar(8),dateadd(dd,number,'2010-01-01'),112)
from
(select number from master..spt ......