SQL字符串处理，添查询加行号，SQL修改带索引的表结构

--移除某些字符 

SET @Code_Num = REPLACE(@Code, @Pre, '');

--取左侧N位

set @Old_TodayNow =left(@Code_Num,len(@Code_Num)-@SNLength)

--获取年月，月份获取两位时注意先转成字符串类型再取

SET @TodayNow = RIGHT(YEAR(GETDATE()), @YearLength)  + RIGHT('00'+ CAST(MONTH(GETDATE()) as nvarchar(20)), 2)  
--对比是否存在相同的字符

IF CHARINDEX('人事', @EmpRoles) > 0 

--拆解拼接字符串

 select  col from [dbo].[f_split]( @EmpIds,'/')

　--补零

SET @SheetNo = @ProjectNo + '_' + RIGHT('000000000' + cast(@SerNo as Nvarchar(100)),3)

--替换一个字段中的部分字符 
update [dbo].[GB_FloVersionInfor]  set CustomExpression=REPLACE(CustomExpression,'ProjectDepID','CompanyID')
  where [BaseMenuID] IN (SELECT ID FROM SY_MENU
WHERE frmName  = 'Purchase/PC_PR/PagePC_PR.xaml') and CustomExpression like '%ProjectDepID%'

--为查询数据额外添加序号

Select identity(int,1,1) As R,* Into #Tmp
			From  [dbo].[f_split](@SheetNo,'_')
			Select TOP 1 @SericeNo =   col From #Tmp 
			ORDER BY R desc
			Drop Table #Tmp

--修改带索引的数据库字段

drop index [IX_BD_Material] on [BD_Material] ;
ALTER TABLE [BD_Material] ALTER COLUMN Code NVARCHAR(100)
create unique index [IX_BD_Material] on [BD_Material](Code)
go