=20&MID(A1,2,2)& "-" &MID(A1,4,2)& "-" &MID(A1,6,2)
B1输入：=TEXT(MID(A1,2,6),"2000-00-00")下拉即可
=TEXT(MID(A1,2,6),"2000-00-00")或=20&TEXT(MID(A1,2,6),"00-00-00")
=TEXT(20&MID(A1,2,6),"0000-00-00")
