sql语句.doc

创建数据库创建之前判断该数据库是否存在ifexists(select*fromsysdatabaseswherename='databaseName')dropdatabasedatabaseNamegoCreateDATABASEdatabase-name删除数据库dropdatabasedbname备份sqlserver---创建备份数据的deviceUSEmasterEXECsp_addumpdevice'disk','testBack','c:\mssql7backup\'---开始备份BACKUPDATABASEpubsTOtestBack创建新表createtabletabname(col1type1[notnull][primarykey],col2type2[notnull],..)根据已有的表创建新表:A:gouse原数据库名goselect*(使用旧表创建新表)B:createtabletab_newasselectcol1,col2…fromtab_olddefinitiononly创建序列createsequenceSIMON_SEQUENCEminvalue1--最小值maxvalue999999999最大值startwith1开始值incrementby1每次加几cache20;删除新表droptabletabname增加一个列Altertabletabnameaddcolumncoltype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。添加主键Altertabletabnameaddprimarykey(col)说明:删除主键:Altertabletabnamedropprimarykey(col)创建索引create[unique]indexidxnameontabname(col…。)删除索引:dropindexidxnameontabname注:索引是不可更改的,想更改必须删除重新建。创建视图createviewviewnameasselectstatement删除视图:dropviewviewname几个简单的基本的sql语句选择:select*fromtable1where范围插入:insertintotable1(field1,field2)values(value1,value2)删除:deletefromtable1where范围更新:updatetable1setfield1=value1where范围查找:select*fromtable1wherefield1like’%value1%’(所有包含‘value1’这个模式的字符串)---like的语法很精妙,查资料!排序:select*fromtable1orderbyfield1,field2[desc]分组:select*fromtable1groupbyfield1ORDERBYcount(ShopId)LIMIT20(兼并排序分页)总数:selectcount(*)astotalcountfromtable1求和:selectsum(field1)assumvaluefromtable1平均:selectav