一个比较难的问题（高手请进）

do not make 序号 as identity column, then when you delete 西红柿,

declare @id int
select @id = 序号 where 名称 = '西红柿'
delete from yourtable where 序号 = @id
update yourtable set 序号 = 序号 -1 where 序号 > @id

序号是每次都要变的，
并且不受用户控制，
序号完全的标识了
一共有多少记录让人一看就明白

that is just a demo, try

Create proc DeleteFruit
@name nvarchar(100)
as
declare @id int
select @id = 序号 from yourtable where 名称 = @name
delete from yourtable where 序号 = @id
update yourtable set 序号 = 序号 -1 where 序号 > @id

then call

DeleteFruit '西红柿'

谢谢各位