Append Query中如何加入一个自动编号的值?

Append Query中如何加入一个自动编号的值?例如下面的SQL语句

INSERT INTO sample ( stockID,Bgnny, strMatName, strSpc, Qty, opertime )
SELECT ?????,IIf(Month(Date())=12,Format(DateSerial(Year(Date()),Month(Date())+1,Day(Date())),"yyyymm"),Format(Date(),"yyyymm")) AS 年月, CurrentStock.备件名称, CurrentStock.备件规格, CurrentStock.现在库存, Now() AS opertime
FROM CurrentStock LEFT JOIN sample ON (CurrentStock.年月 = sample.Bgnny) AND (CurrentStock.备件规格 = sample.strSpc) AND (CurrentStock.备件名称 = sample.strMatName)
WHERE (((sample.Bgnny) Is Null));

?????即为要自动编号的字段,编号的形式为 "2008120001",依次递增!
请教各位老师!