三、技巧

1、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 !=''''

begin

set @strSQL = ''select count(*) as Total from ['' + @tblName + ''] where '' + @strWhere

end

else

begin

set @strSQL = ''select count(*) as Total from ['' + @tblName + '']''

end

我们可以直接写成

错误！未找到目录项。

set @strSQL = ''select count(*) as Total from ['' + @tblName + ''] where 1=1安定''+ @strWhere2、收缩数据库

--重建索引

DBCC REINDEX

DBCC INDEXDEFRAG

--收缩数据和日志

DBCC SHRINKDB

DBCC SHRINKFILE

3、压缩数据库

dbcc shrinkdatabase(dbname)

4、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

5、检查备份集

RESTORE VERIFYONLY from disk=''E:/dvbbs.bak''

6、修复数据库

ALTER DATABASE [dvbbs] SET SINGLE_USER

GO

DBCC CHECKDB(''dvbbs'',repair_allow_data_loss) WITH TABLOCK

GO

ALTER DATABASE [dvbbs] SET MULTI_USER

GO

7、日志清除

SET NOCOUNT ON

DECLARE @LogicalFileName sysname,

@MaxMinutes INT,

@NewSize INT

USE 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 / initialize

DECLARE @OriginalSize int

SELECT @OriginalSize = size

FROM sysfiles

WHERE name = @LogicalFileName

SELECT ''Original Size of '' + db_name() + '' LOG is '' +

CONVERT(VARCHAR(30),@OriginalSize) + '' 8K pages or '' +

CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + ''MB''

FROM sysfiles

WHERE name = @LogicalFileName

CREATE TABLE DummyTrans

(DummyColumn char (8000) not null)

DECLARE @Counter INT,

@StartTime DATETIME,

@TruncLog VARCHAR(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 expired

AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName)

AND (@OriginalSize * 8 /1024) > @NewSize

BEGIN -- Outer loop.

SELECT @Counter = 0

WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000))

BEGIN -- update

INSERT DummyTrans VALUES (''Fill Log'') DELETE DummyTrans

SELECT @Counter = @Counter + 1

END

EXEC (@TruncLog)

END

SELECT ''Final Size of '' + db_name() + '' LOG is '' +

CONVERT(VARCHAR(30),size) + '' 8K pages or '' +

CONVERT(VARCHAR(30),(size*8/1024)) + ''MB''

FROM sysfiles

WHERE name = @LogicalFileName

DROP TABLE DummyTrans

SET NOCOUNT OFF

8、说明：更改某个表

exec sp_changeobjectowner ''tablename'',''dbo''

9、存储更改全部表

CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch

@OldOwner as NVARCHAR(128),

@NewOwner as NVARCHAR(128)

AS

DECLARE @Name as NVARCHAR(128)

DECLARE @Owner as NVARCHAR(128)

DECLARE @OwnerName as NVARCHAR(128)

DECLARE curObject CURSOR FOR

select ''Name'' = name,

''Owner'' = user_name(uid)

from sysobjects

where user_name(uid)=@OldOwner

order by name

OPEN curObject

FETCH NEXT FROM curObject INTO @Name, @Owner

WHILE(@@FETCH_STATUS=0)

BEGIN

if @Owner=@OldOwner

begin

set @OwnerName = @OldOwner + ''.'' + rtrim(@Name)

exec sp_changeobjectowner @OwnerName, @NewOwner

end

-- select @name,@NewOwner,@OldOwner

FETCH NEXT FROM curObject INTO @Name, @Owner

END

close curObject

deallocate curObject

GO

10、SQL SERVER中直接循环写入数据

declare @i int

set @i=1

while @i<30

begin

insert into test (userid) values(@i)

set @i=@i+1

end

案例：

有如下表，要求就裱中所有沒有及格的成績，在每次增長0.1的基礎上，使他們剛好及格:

Namescore

Zhangshan80

Lishi59

Wangwu50

Songquan69

while((selectmin(score) from tb_table)<60)

begin

update tb_table set score=score*1.01

where score<60

if(selectmin(score) from tb_table)>60

break

else

continue

end