Óà SqlÌí¼Óɾ³ý×ֶΣ¬ÅжÏ×Ö¶ÎÊÇ·ñ´æÔڵķ½·¨

http://www.cnblogs.com/dwjaissk/archive/2006/07/25/459476.aspx
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alter table docdsp  add dspcode char(200)
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ALTER TABLE
table_NAME DROP COLUMN column_NAME
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ALTER TABLE table_name 
ALTER COLUMN column_name new_data_type
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sp_rename
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sp_rename [ @objname = ] 'object_name' ,
    [ @newname = ]
'new_name'
    [ , [ @objtype = ] 'object_type' ]
--¼ÙÉèÒª´¦ÀíµÄ±íÃûΪ: tb
--ÅжÏÒªÌí¼ÓÁеıíÖÐÊÇ·ñÓÐÖ÷¼ü
if exists(select 1 from sysobjects where
parent_obj=object_id('tb') and xtype='PK')
begin
 print
'±íÖÐÒѾ­ÓÐÖ÷¼ü,ÁÐÖ»ÄÜ×öΪÆÕͨÁÐÌí¼Ó'
 --Ìí¼ÓintÀàÐ͵ÄÁÐ,ĬÈÏֵΪ0
 alter table tb add ÁÐÃû int default 0 
end
else
begin
 print
'±íÖÐÎÞÖ÷¼ü,Ìí¼ÓÖ÷¼üÁÐ'
 --Ìí¼ÓintÀàÐ͵ÄÁÐ,ĬÈÏֵΪ0
 alter table tb add ÁÐÃû int primary key default
0 
end
/**************************************************************************************/
ÅÐ
¶Ïtable1ÖÐÊÇ·ñ´æÔÚname×Ö¶Î
if exists(select * from syscolumns where
id=object_id('table1') and name='name') begin
select * from people;
end