I would like to ask on how to convert this query to an arrayformula:
=query({unique(filter(A$2:A,B$2:B=B2)),sequence(rows(unique(filter(A$2:A,B$2:B=B2))))},"select Col2 where Col1 = '"&A2&"'")
I also attached this in a gsheet: 
CodePudding user response：
One option would be to use an Apps Script 
