Extracting the 1 level lower part numbers based on Level numbers in multi level BoM

Hello Friends

Based on the column A `Level number' 1 level lower part numbers to be plotted as shown in the light yellow column D as results by formulas.

Note :
* Level `0' part numbers will usually more than one and different part numbers, but here only one `0' part number available.
* In Light yellow cells results need to be produced for all cells but shown only for some cells for illustration purpose.

Thanks in advance

Sekar

Please try

D2
=IF(A2>0,INDEX(B$1:B2,AGGREGATE(14,6,ROW(A$1:A2)/(1/(A$1:A2=A2-1)),1)),"--")

Regards.

In D2 then copy down

=IFERROR(LOOKUP(2,1/($A$1:$A1=(A2-1)),$B$1:$B1),"")

Thanks to all. This is helped me to save my manual work time.