=TEXT(MID(A1,7,6+(LEN(A1)=18)*2),"#-00-00")+0
=TEXT(MID(A1,7,6+(LEN(A1)=18)*2),"#-00-00")*1
=IF(A2<>"",TEXT((LEN(A2)=15)*19&MID(A2,7,6+(LEN(A2)=18)*2),"#-00-00")+0,) yyyy-m-d
=IF(LEN(A2)=15,"19"&MID(A2,7,2)&"-"&MID(A2,9,2)&"-"&MID(A2,11,2),MID(A2,7,4)&
"-"&MID(A2,11,2)&"-"&MID(A2,13,2))