基础创建数据库 创建之前判断该数据库是否存在if exists (select * from sysdatabases where name='databaseName') drop database databaseNamegoCreate DATABASE database-name删除数据库 drop database dbname备份sql ser er --- 创建 备份数据的 de iceUSE masterEXEC sp_addumpde ice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat'--- 开始 备份BACKUP DATABASE pubs TO testBack创建新表 create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..)根据已有的表创建新表:A:create table tab_new like tab_old (使用旧表创建新表)B:create table tab_new as select col1,col2… from tab_old definition only创建序列 create sequence SIMON_SEQUENCE min alue 1 -- 最小值 max alue 999999999999999999999999999 最大值start with 1 开始值increment by 1 每次加几cache 20;删除新表 drop table tabname增加一个列 Alter table tabname add column col type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 archar类型的长度。添加主键 Alter table tabname add primary key(col)说明:删除主键: Alter table tabname drop primary key(col)创建索引 create [unique] index idxname on tabname(col….)删除索引:drop index idxname on tabname注:索引是不可更改的,想更改必须删除重新建。创建视图 create iew iewname as select statement删除视图:drop iew iewname几个简单的基本的sql语句 选择:select * from table1 where 范围插入:insert into table1(field1,field2) alues( alue1, alue2)删除:delete from table1 where 范围更新:update table1 set field1= alue1 where 范围查找:select * from table1 where field1 like ’% alue1%’ (所有包含‘ alue1’这个模式的字符串)---like的语法很精妙,查资料!排序:select * from table1 order by field1,field2 [desc]总数:select count(*) as totalcount from table1求和:select sum(field1) as sum alue from table1平均:select a g(field1) as a g alue from table1最大:select max(field1) as max alue from table1最小:select min(field1) as min alue from table1[separator]几个高级查询运算词 A: UNION 运算符UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。B: EXCEPT 运算符EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。C: INTERSECT 运算符INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。注:使用运算词的几个查询结果行必须是一致的。使用外连接 A、left outer join:左外连接(左连接):结果集既包括连接表的匹配行,也包括左连接表的所有行。SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.cB:right outer join:右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。C:full outer join:全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。[编辑本段]提升复制表 (只复制结构,源表名:a 新表名:b) (Access可用)法一:select * into b from a where 1<>1法二:select top 0 * into b from a拷贝表 (拷贝数据,源表名:a 目标表名:b) (Access可用)insert into b(a, b, c) select d,e,f from b;跨数据库之间表的拷贝 (具体数据使用绝对路径) (Access可用)insert into b(a, b, c) select d,e,f from b in ‘具体数据库’ where 条件例子:..from b in '"&Ser er.MapPath("."&"\data.mdb" &"' where..子查询 (表名1:a 表名2:b)select a,b,c from a where a IN (select d from b 或者: select a,b,c from a where a IN (1,2,3)显示文章、提交人和最后回复时间 select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b外连接查询 (表名1:a 表名2:b)select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c在线视图查询 (表名1:aselect * from (Select a,b,c FROM a) T where t.a > 1;between的用法 between限制查询数据范围时包括了边界值,not between不包括select * from table1 where time between time1 and time2select a,b,c, from table1 where a not between 数值1 and 数值2in 的使用方法 select * from table1 where a [not] in (‘值1’,’值2’,’值4’,’值6’)删除主表中已经在副表中没有的信息 两张关联表delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1四表联查问题 select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where .....日程安排提前五分钟提醒 SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5一条sql 语句搞定数据库分页 select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段前10条记录 select top 10 * form table1 where 范围选择排名 选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.)select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b)派生结果表 包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表(select a from tableA except (select a from tableB) except (select a from tableC)随机取出10条数据 select top 10 * from tablename order by newid()随机选择记录 select newid()删除重复记录 Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...)列出数据库里所有的表名 select name from sysobjects where type='U'列出表里的所有的 select name from syscolumns where id=object_id('TableName')列示排列 列示type、 ender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。select type,sum(case ender when 'A' then pcs else 0 end),sum(case ender when 'C' then pcs else 0 end),sum(case ender when 'B' then pcs else 0 end) FROM tablename group by type显示结果:type ender pcs电脑 A 1电脑 A 1光盘 B 2光盘 A 2手机 B 3手机 C 3初始化表table1 TRUNCATE TABLE table1选择从10到15的记录 select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc数据类型转换 declare @numid intdeclare @id archar(50)set @numid=2005set @id=con ert( archar,@numid)通过上述语句完成数据类型Int转换成 archar,其他转换类似,可参看con ert函数[编辑本段]技巧1=1,1=2的使用 在SQL语句组合时用的较多“where 1=1” 是表示选择全部 “where 1=2”全部不选,如:if @strWhere !='beginset @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhereendelsebeginset @strSQL = 'select count(*) as Total from [' + @tblName + ']'end我们可以直接写成set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 and '+ @strWhere收缩数据库 --重建索引DBCC REINDEXDBCC INDEXDEFRAG--收缩数据和日志DBCC SHRINKDBDBCC SHRINKFILE压缩数据库 dbcc shrinkdatabase(dbname)转移数据库给新用户以已存在用户权限exec sp_change_users_login 'update_one','newname','oldname'go检查备份集 RESTORE ERIFYONLY from disk='E:\\d <br />bbs.bak'修复数据库 Alter DATABASE [d bbs] SET SINGLE_USERGODBCC CHECKDB('d bbs',repair_allow_data_loss) WITH TABLOCKGOAlter DATABASE [d bbs] SET MULTI_USERGO日志清除 SET NOCOUNT ONDECLARE @LogicalFileName sysname,@MaxMinutes INT,@NewSize INTUSE tablename -- 要操作的数据库名Select @LogicalFileName = 'tablename_log', -- 日志文件名@MaxMinutes = 10, -- Limit on time allowed to wrap log.@NewSize = 1 -- 你想设定的日志文件的大小(M)-- Setup / initializeDECLARE @OriginalSize intSelect @OriginalSize = sizeFROM sysfilesWhere name = @LogicalFileNameSelect 'Original Size of ' + db_name() + ' LOG is ' +CON ERT( ARCHAR(30),@OriginalSize) + ' 8K pages or ' +CON ERT( ARCHAR(30),(@OriginalSize*8/1024)) + 'MB'FROM sysfilesWhere name = @LogicalFileNameCreate TABLE DummyTrans(DummyColumn char (8000) not null)DECLARE @Counter INT,@StartTime DATETIME,@TruncLog ARCHAR(255)Select @StartTime = GETDATE(),@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY'DBCC SHRINKFILE (@LogicalFileName, @NewSize)EXEC (@TruncLog)-- Wrap the log if necessary.WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expiredAND @OriginalSize = (Select size FROM sysfiles Where name = @LogicalFileName)AND (@OriginalSize * 8 /1024) > @NewSizeBEGIN -- Outer loop.Select @Counter = 0WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000))BEGIN -- updateInsert DummyTrans ALUES ('Fill Log')Delete DummyTransSelect @Counter = @Counter + 1ENDEXEC (@TruncLog)ENDSelect 'Final Size of ' + db_name() + ' LOG is ' +CON ERT( ARCHAR(30),size) + ' 8K pages or ' +CON ERT( ARCHAR(30),(size*8/1024)) + 'MB'FROM sysfilesWhere name = @LogicalFileNameDrop TABLE DummyTransSET NOCOUNT OFF更改某个表 exec sp_changeobjectowner 'tablename','dbo'存储更改全部表 Create PROCEDURE dbo.User_ChangeObjectOwnerBatch@OldOwner as N ARCHAR(128),@NewOwner as N ARCHAR(128)ASDECLARE @Name as N ARCHAR(128)DECLARE @Owner as N ARCHAR(128)DECLARE @OwnerName as N ARCHAR(128)DECLARE curObject CURSOR FORselect 'Name' = name,'Owner' = user_name(uid)from sysobjectswhere user_name(uid)=@OldOwnerorder by nameOPEN curObjectFETCH NEXT FROM curObject INTO @Name, @OwnerWHILE(@@FETCH_STATUS=0)BEGINif @Owner=@OldOwnerbeginset @OwnerName = @OldOwner + '.' + rtrim(@Name)exec sp_changeobjectowner @OwnerName, @NewOwnerend-- select @name,@NewOwner,@OldOwnerFETCH NEXT FROM curObject INTO @Name, @OwnerENDclose curObjectdeallocate curObjectGOSQL SER ER中直接循环写入数据 declare @i intset @i=1while @i<30begininsert into test (userid) alues(@i)set @i=@i+1end
本文转自06peng 51CTO博客,原文链接:http://blog.51cto.com/06peng/962372,如需转载请自行联系原作者