给表insert一条新数据，除了一个字段其他字段的值和上一条数据的值一样

[Ίκαρος]

POLICYNO ITEMNO RISKCODE ITEMCODE

060101012015000001 1 0101 01

060101012015000002 1 0101 01

060101012015000002 2 0101 01

060101012015000003 1 0101 01

新增的数据的POLICYNO = 060101012015000002 ITEMNO是POLICYNO = 060101012015000002的数据的最大值+1其他字段和当前ITEMNO最大值 的那条数据的值一样 要怎么写，求大佬帮忙

[脆皮大雪糕]

insert into tablename 
select '060101012015000003',t1.ITEMNO,t1.RISKCODE,t1.ITEMCODE
from tablename t1,
(select  POLICYNO,  max(ITEMNO）as itemno from tablename group by POLICYNO ) t2
where t1.POLICYNO = t2.POLICYNO and t1.ITEMNO = t2. ITEMNO and t1.POLICYNO = '060101012015000002'