Finding duplicates in a column(QlikSense)

[achakilam1022]

I have  a data table containing columns id, date, phone and the column flag which i want to modify (1 for unique and 0 for duplicate)

I want to find duplicates in phone column and mark flag based on date. Eg: If the same phone number appears thrice in the column then the earliest record (based on date) should be marked as 1 and remaining two records(duplicates) should be marked as 0.

Expected Output : date format : dd/mm/yyyy

thank you.

[achakilam1022]

Thanks again