如果已经存在用户名 则自动生成一个用户名使用用户名加数字

declare @oid nvarchar(50)
set @oid="huangf"
select top 1 ISNULL(oid,""),SUBSTRING(oid,LEN(@oid )+1,LEN(oid )),case  ISNUMERIC(SUBSTRING(oid,LEN(@oid )+1,LEN(oid ))) when 1 then CONVERT(int,SUBSTRING(oid,LEN(@oid )+1,LEN(oid ))) else 0 end as num from AOinfo  where oid like @oid+"%"
order by num desc