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终于等到你, “满级”SQL语句技巧大全笔记,太全面了,已跪

火热如冰 2022-02-09 阅读 58

 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

2、压缩数据库
dbcc shrinkdatabase(dbname)

 3、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

 4、检查备份集
RESTORE VERIFYONLY from disk='E:\dvbbs.bak'

 5、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

 6、说明:更改某个表
exec sp_changeobjectowner 'tablename','dbo'

7、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

 8、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

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