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 '+ @strWhere 

 

 

2、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:

 

Name     score

Zhangshan   80

Lishi       59

Wangwu      50

Songquan    69

while((select min(score) from tb_table)<60)

begin

update tb_table set score =score*1.01

where score<60

if  (select min(score) from tb_table)>60

break

else

continue

end

 

 

 SQL相关链接：

SQL语句大全 —《基础》：https://www.songqinnet.com/article/916

SQL语句大全 —《提升》：https://www.songqinnet.com/article/917

SQL语句大全 —《技巧》：https://www.songqinnet.com/article/920

SQL语句大全 —《解决方案》：https://www.songqinnet.com/article/923