sql server中怎么截取字符串

Question

declare @Userinfo varchar(50)
set @Userinfo='admin@123'
怎么将admin截取出来
很急拜托

Answer 1

select
   left(@userinfo,charindex('@',(@userinfo)-1)

Answer 2

declare @Userinfo varchar(50)
set @Userinfo='admin@123'select
   left(@userinfo,charindex('@',@userinfo)-1)
     --------------------------------------------------
     /*
admin(1 行受影响)*/

Answer 3

declare @Userinfo varchar(50)
set @Userinfo='admin@123'select
   PARSENAME(replace(@Userinfo,'@','.'),2)
   
   /*--------------------------------------------------------------------------------------------------------------------------------
admin(1 行受影响)*/