国产探花免费观看_亚洲丰满少妇自慰呻吟_97日韩有码在线_资源在线日韩欧美_一区二区精品毛片,辰东完美世界有声小说,欢乐颂第一季,yy玄幻小说排行榜完本

首頁 > 開發 > 綜合 > 正文

常用經典SQL語句大全(技巧)

2024-07-21 02:47:50
字體:
來源:轉載
供稿:網友
常用經典SQL語句大全(技巧)三、技巧

1、1=1,1=2的使用,在SQL語句組合時用的較多

“where 1=1” 是表示選擇全部 “where 1=2”全部不選,

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

我們可以直接寫成

錯誤!未找到目錄項。

set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere

2、收縮數據庫

--重建索引

DBCC REINDEX DBCC INDEXDEFRAG

--收縮數據和日志

DBCC SHRINKDB DBCC SHRINKFILE

3、壓縮數據庫

dbccshrinkdatabase(dbname)

4、轉移數據庫給新用戶以已存在用戶權限

execsp_change_users_login 'update_one','newname','oldname' go

5、檢查備份集

RESTORE VERIFYONLY fromdisk='E:/dvbbs.bak'

6、修復數據庫

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-- 要操作的數據庫名

SELECT @LogicalFileName ='tablename_log', -- 日志文件名

@MaxMinutes = 10, -- Limit on time allowed to wrap log.

@NewSize = 1 -- 你想設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 notexpired AND @OriginalSize = (SELECT size FROMsysfiles 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 pagesor ' + CONVERT(VARCHAR(30),(size*8/1024)) +'MB' FROM sysfiles WHERE name = @LogicalFileName DROP TABLE DummyTrans SET NOCOUNT OFF

8、說明:更改某個表

exec sp_changeobjectowner'tablename','dbo'

9、存儲更改全部表

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中直接循環寫入數據

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


發表評論 共有條評論
用戶名: 密碼:
驗證碼: 匿名發表
主站蜘蛛池模板: 东乡县| 清苑县| 台安县| 南丹县| 汉中市| 香港| 平远县| 饶阳县| 鸡西市| 电白县| 宣威市| 库伦旗| 加查县| 射阳县| 荃湾区| 凌源市| 武汉市| 绥江县| 临夏县| 军事| 吴桥县| 日照市| 宣城市| 延津县| 荔浦县| 阜阳市| 奉贤区| 五寨县| 夏邑县| 上杭县| 濉溪县| 沈丘县| 尉氏县| 鹤峰县| 大庆市| 吴旗县| 手机| 阜平县| 喀喇| 黑山县| 霸州市|