CONCATENATE(format(today(),"yyyyMM"),format(seq(),"000"))

CONCATENATE(format(today(),"yyyyMM"),format(&A2,"000"))

可直接在sql中在表里面写触发器，如

CREATE trigger [dbo].[insert_A]

on  [dbo].[T_ls]

for insert

as

declare @id int

declare @num varchar(10) 

select @id=id from inserted

 IF exists( select 1  from T_LS where  SUBSTRING(序号,3,8)=convert(varchar(8),getdate(),112))

 begin

 select  @num= RIGHT('00000000'+CAST(max(right(序号,4)+1) as varchar(10)),4)   from T_LS where SUBSTRING(序号,3,8)=convert(varchar(8),getdate(),112) GROUP BY 序号

  update T_ls set 序号 ='XN'+convert(varchar(8),getdate(),112)+@num where id=@id

 end

 else 

  begin

 set @num='0001'

  update T_LS set 序号 ='XN'+convert(varchar(8),getdate(),112)+@num where id=@id

 end

GO

ALTER TABLE [dbo].[T_ls] ENABLE TRIGGER [insert_A]

GO