I have a table with 3 columns: day of month, client_uk, flag_login (Y/N). My task is to group this table over by month to determine what flag_login should be for each month for every client. The client could be login a few time per month, for me, it doesn’t matter and I should determine whether the fact of client login at least 1 time per month. If it’s yes flag_login should Y, in opposite case ‘N’.
I don’t know how to solve it, because my window for window function should be client_uk and month simultaneously.
Thanks for the help in advance!