Sql 如何批量把邮箱地址更新成邮箱前缀？
例如 表名 list 字段email_title

如何把字段email_title里面的邮件地址数据，批量操作成邮件前缀，即删除@及@后面的所有字符。

adfdf@163.com 变成 adfdf
fdf@sina.cn 变成 fdf

求批量更新的sql
[解决办法]

----------------------------------------------------------------
-- Author  :DBA_Huangzj()
-- Date    :2013-11-20 13:01:14
-- Version:
--      Microsoft SQL Server 2012 (SP1) - 11.0.3128.0 (X64) 
--Dec 28 2012 20:23:12 
--Copyright (c) Microsoft Corporation
--Enterprise Edition (64-bit) on Windows NT 6.2 <X64> (Build 9200: )
--
----------------------------------------------------------------
--> 测试数据：[list]
if object_id('[list]') is not null drop table [list]
go 
create table [list]([email_title] varchar(13))
insert [list]
select 'adfdf@163.com' union all
select 'fdf@sina.cn'
--------------开始查询--------------------------

select SUBSTRING([email_title],1,PATINDEX('%@%',[email_title])-1)
 from [list]
----------------结果----------------------------
/* 
-------------
adfdf
fdf

*/

--drop table tb
--go


create table tb(v nvarchar(20))

insert into tb
select 'adfdf@163.com' 
union all select 'fdf@sina.cn'

;with t
as
(
select v,left(v,CHARINDEX('@',v)-1) vv
from tb
)

--更新数据
update t
set v = vv


--更新后,查询数据,已经更新
select *
from tb
/*
v
adfdf
fdf
*/

select 'adfdf@163.com'  email_title
into #list
union all select 'fdf@sina.cn'
------------开始查询--------------------------

select *
from #list

;with t as
(
select [email_title]
,stuff([email_title],PATINDEX('%@%',[email_title]),LEN([email_title])-PATINDEX('%@%',[email_title])+1,'') email_title1
 from #list
 )
update #list
set email_title=email_title1
from t
join #list t2
on t.email_title=t2.email_title

select * 
from #list
----------------结果----------------------------
/* 
-------------
adfdf
fdf
*/

--出现这错误,说明你的某些记录中email_title字段没有关键字@
update list set email_title=case when PATINDEX('%@%',[email_title])>1
 then substring([email_title],1,PATINDEX('%@%',[email_title])-1) 
 else email_title end