Here below is an annual and quarterly sales data table:

In this table, column A is ordered and has duplicate values. Now we want to clear the data from all rows in the same group except the first row.

=spl("=E(?1).group(#1).(~.run(if(#==1,,#1=null))).conj()",A1:C21)

esProc Desktop and Excel Processing
7.11 Calculate using adjacent row/interval when data of the same group is discontinuous (LRR/YOY in the case of missing data)
7.13 String concatenation and aggregation