awk group by multiple columns and print max value with non-primary key

Question

i\'m new to this site and trying to learn awk. i\'m trying to find the maximum value of field3, grouping by field1 and print all the fields with maximum value. Field 2 contains

Answer 1

With a little help of the sort command:

sort -t, -k1,1 -k3,3nr file | awk -F, '!seen[$1]++'