精妙SQL速查手册
<P>一、基础<BR>1、说明：创建数据库<BR>CREATE DATABASE database-name<BR>2、说明：删除数据库<BR>drop database dbname<BR>3、说明：备份sql server<BR>--- 创建 备份数据的 device<BR>USE master<BR>EXEC sp_addumpdevice 'disk', 'testBack', 'c:mssql7backupMyNwind_1.dat'<BR>--- 开始 备份<BR>BACKUP DATABASE pubs TO testBack<BR>4、说明：创建新表<BR>create table tabname(col1 type1 ,col2 type2 ,..)<BR>根据已有的表创建新表：<BR>A：create table tab_new like tab_old (使用旧表创建新表)<BR>B：create table tab_new as select col1,col2... from tab_old definition only<BR>5、说明：删除新表<BR>drop table tabname<BR>6、说明：增加一个列<BR>Alter table tabname add column col type<BR>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。<BR>7、说明：添加主键： Alter table tabname add primary key(col)<BR>说明：删除主键： Alter table tabname drop primary key(col)<BR>8、说明：创建索引：create index idxname on tabname(col....)<BR>删除索引：drop index idxname<BR>注：索引是不可更改的，想更改必须删除重新建。<BR>9、说明：创建视图：create view viewname as select statement<BR>删除视图：drop view viewname<BR>10、说明：几个简单的基本的sql语句<BR>选择：select * from table1 where 范围<BR>插入：insert into table1(field1,field2) values(value1,value2)<BR>删除：delete from table1 where 范围<BR>更新：update table1 set field1=value1 where 范围<BR>查找：select * from table1 where field1 like '%value1%' ---like的语法很精妙，查资料!<BR>排序：select * from table1 order by field1,field2 <BR>总数：select count as totalcount from table1<BR>求和：select sum(field1) as sumvalue from table1<BR>平均：select avg(field1) as avgvalue from table1<BR>最大：select max(field1) as maxvalue from table1<BR>最小：select min(field1) as minvalue from table1<BR>11、说明：几个高级查询运算词<BR>A： UNION 运算符<BR>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。<BR>B： EXCEPT 运算符<BR>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。<BR>C： INTERSECT 运算符<BR>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。<BR>注：使用运算词的几个查询结果行必须是一致的。<BR>12、说明：使用外连接<BR>A、left outer join：<BR>左外连接（左连接）：结果集几包括连接表的匹配行，也包括左连接表的所有行。<BR>SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c<BR>B：right outer join:<BR>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。<BR>C：full outer join：<BR>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。</P><P><BR>二、提升<BR>1、说明：复制表(只复制结构,源表名：a 新表名：b) (Access可用)<BR>法一：select * into b from a where 1<>1<BR>法二：select top 0 * into b from a<BR>2、说明：拷贝表(拷贝数据,源表名：a 目标表名：b) (Access可用)<BR>insert into b(a, b, c) select d,e,f from b;<BR>3、说明：跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用)<BR>insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件<BR>例子：..from b in '"&Server.MapPath(".")&"data.mdb" &"' where..<BR>4、说明：子查询(表名1：a 表名2：b)<BR>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)<BR>5、说明：显示文章、提交人和最后回复时间<BR>select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b<BR>6、说明：外连接查询(表名1：a 表名2：b)<BR>select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c<BR>7、说明：在线视图查询(表名1：a )<BR>select * from (SELECT a,b,c FROM a) T where t.a > 1;<BR>8、说明：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<BR>select * from table1 where time between time1 and time2<BR>select a,b,c, from table1 where a not between 数值1 and 数值2<BR>9、说明：in 的使用方法<BR>select * from table1 where a in ('值1','值2','值4','值6')<BR>10、说明：两张关联表，删除主表中已经在副表中没有的信息<BR>delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 )<BR>11、说明：四表联查问题：<BR>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 .....<BR>12、说明：日程安排提前五分钟提醒<BR>SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5<BR>13、说明：一条sql 语句搞定数据库分页<BR>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<BR>14、说明：前10条记录<BR>select top 10 * form table1 where 范围<BR>15、说明：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.)<BR>select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b)<BR>16、说明：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<BR>(select a from tableA ) except (select a from tableB) except (select a from tableC)<BR>17、说明：随机取出10条数据<BR>select top 10 * from tablename order by newid()<BR>18、说明：随机选择记录<BR>select newid()<BR>19、说明：删除重复记录<BR>Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...)<BR>20、说明：列出数据库里所有的表名<BR>select name from sysobjects where type='U'<BR>21、说明：列出表里的所有的<BR>select name from syscolumns where id=object_id('TableName')<BR>22、说明：列示type、vender、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。<BR>select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type<BR>显示结果：<BR>type vender pcs<BR>电脑 A 1<BR>电脑 A 1<BR>光盘 B 2<BR>光盘 A 2<BR>手机 B 3<BR>手机 C 3<BR>23、说明：初始化表table1<BR>TRUNCATE TABLE table1<BR>24、说明：选择从10到15的记录<BR>select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc</P>
<P>三、技巧<BR>1、1=1，1=2的使用，在SQL语句组合时用的较多<BR>"where 1=1" 是表示选择全部 "where 1=2"全部不选，<BR>如：<BR>if @strWhere !=''<BR>begin<BR>set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere<BR>end<BR>else<BR>begin<BR>set @strSQL = 'select count(*) as Total from [' + @tblName + ']'<BR>end<BR>我们可以直接写成<BR>set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere<BR>2、收缩数据库<BR>--重建索引<BR>DBCC REINDEX<BR>DBCC INDEXDEFRAG<BR>--收缩数据和日志<BR>DBCC SHRINKDB<BR>DBCC SHRINKFILE<BR>3、压缩数据库<BR>dbcc shrinkdatabase(dbname)<BR>4、转移数据库给新用户以已存在用户权限<BR>exec sp_change_users_login 'update_one','newname','oldname'<BR>go<BR>5、检查备份集<BR>RESTORE VERIFYONLY from disk='E:dvbbs.bak'<BR>6、修复数据库<BR>ALTER DATABASE SET SINGLE_USER<BR>GO<BR>DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK<BR>GO<BR>ALTER DATABASE SET MULTI_USER<BR>GO<BR>7、日志清除<BR>SET NOCOUNT ON<BR>DECLARE @LogicalFileName sysname,<BR> @MaxMinutes INT,<BR> @NewSize INT</P>
<P>USE tablename -- 要操作的数据库名<BR>SELECT @LogicalFileName = 'tablename_log', -- 日志文件名<BR>@MaxMinutes = 10, -- Limit on time allowed to wrap log.<BR> @NewSize = 1 -- 你想设定的日志文件的大小(M)<BR>-- Setup / initialize<BR>DECLARE @OriginalSize int<BR>SELECT @OriginalSize = size<BR> FROM sysfiles<BR> WHERE name = @LogicalFileName<BR>SELECT 'Original Size of ' + db_name() + ' LOG is ' +<BR> CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' +<BR> CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB'<BR> FROM sysfiles<BR> WHERE name = @LogicalFileName<BR>CREATE TABLE DummyTrans<BR> (DummyColumn char (8000) not null)</P>
<P>DECLARE @Counter INT,<BR> @StartTime DATETIME,<BR> @TruncLog VARCHAR(255)<BR>SELECT @StartTime = GETDATE(),<BR> @TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY'<BR>DBCC SHRINKFILE (@LogicalFileName, @NewSize)<BR>EXEC (@TruncLog)<BR>-- Wrap the log if necessary.<BR>WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired<BR> AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) <BR> AND (@OriginalSize * 8 /1024) > @NewSize <BR> BEGIN -- Outer loop.<BR> SELECT @Counter = 0<BR> WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000))<BR> BEGIN -- update<BR> INSERT DummyTrans VALUES ('Fill Log') <BR> DELETE DummyTrans<BR> SELECT @Counter = @Counter + 1<BR> END <BR> EXEC (@TruncLog) <BR> END <BR>SELECT 'Final Size of ' + db_name() + ' LOG is ' +<BR> CONVERT(VARCHAR(30),size) + ' 8K pages or ' +<BR> CONVERT(VARCHAR(30),(size*8/1024)) + 'MB'<BR> FROM sysfiles<BR> WHERE name = @LogicalFileName<BR>DROP TABLE DummyTrans<BR>SET NOCOUNT OFF<BR>8、说明：更改某个表<BR>exec sp_changeobjectowner 'tablename','dbo'<BR>9、存储更改全部表<BR>CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch<BR> @OldOwner as NVARCHAR(128),<BR> @NewOwner as NVARCHAR(128)<BR>AS<BR>DECLARE @Name as NVARCHAR(128)<BR>DECLARE @Owner as NVARCHAR(128)<BR>DECLARE @OwnerName as NVARCHAR(128)<BR>DECLARE curObject CURSOR FOR<BR> select 'Name' = name,<BR> 'Owner' = user_name(uid)<BR> from sysobjects<BR> where user_name(uid)=@OldOwner<BR> order by name<BR>OPEN curObject<BR>FETCH NEXT FROM curObject INTO @Name, @Owner<BR>WHILE(@@FETCH_STATUS=0)<BR>BEGIN <BR> if @Owner=@OldOwner<BR> begin<BR> set @OwnerName = @OldOwner + '.' + rtrim(@Name)<BR> exec sp_changeobjectowner @OwnerName, @NewOwner<BR> end<BR>-- select @name,@NewOwner,@OldOwner<BR> FETCH NEXT FROM curObject INTO @Name, @Owner<BR>END<BR>close curObject<BR>deallocate curObject<BR>GO</P>
<P>10、SQL SERVER中直接循环写入数据<BR>declare @i int<BR>set @i=1<BR>while @i<30<BR>begin<BR> insert into test (userid) values(@i)<BR> set @i=@i+1<BR>end<BR>小记存储过程中经常用到的本周，本月，本年函数<BR>Dateadd(wk,datediff(wk,0,getdate()),-1)<BR>Dateadd(wk,datediff(wk,0,getdate()),6)<BR>Dateadd(mm,datediff(mm,0,getdate()),0)<BR>Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0))<BR>Dateadd(yy,datediff(yy,0,getdate()),0)<BR>Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0))<BR>上面的SQL代码只是一个时间段<BR>Dateadd(wk,datediff(wk,0,getdate()),-1)<BR>Dateadd(wk,datediff(wk,0,getdate()),6)<BR>就是表示本周时间段.<BR>下面的SQL的条件部分,就是查询时间段在本周范围内的:<BR>Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6)<BR>而在存储过程中<BR>select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1)<BR>select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6)<BR></P>
re:精妙SQL速查手册
<P>呵呵....生日开心......</P>
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