How to change date format (from yyyy-MM-DD to yyyy-MM)

Question

I'm trying to change date format from yyyy-MM-dd to yyyy-MM .

Ultimately I want to be able to sum and group by month. So far the only working solution I found is adding concat(year(join_data["firstVisit"]), lit("-"), month(join_data["firstVisit"])).alias('firstVisitMonth') in my select statement but then it return the column as a string and I can't sort it correctly.

Answer 1

Try date_format :

date_format(join_data["firstVisit"], 'yyyy-MM')