Select records based on max(date)

Question

Hi everyone,
I have a table (tbl_training) with training information-such as who took what training, when they took it, scores they received and other various stuff.
In this table, a person could have taken multiple training within the year. what i need to see in my results is, the last training the person took. I assume i am looking to query something that produces max(date_of_training) and maybe grouping my id_number. I have tried various combinations of sub-queries to no avail. Any help is welcomed.
So my data may look something like this:
id_number date_of_training score last_name first_name instructor rank
1234 01/01/09 50 doe john mr. hank sgt
1234 02/13/09 72 doe john mr. hank sgt
1234 01/31/09 60 doe john mr. hank sgt
5678 02/03/09 80 smith lisa mr. hank cpl
What i need returned in the query is:
1234 02/13/09 72 doe john mr. hank sgt
5678 02/03/09 80 smith lisa mr. hank cpl
Select id_number, date_of_training, score, last_name, first_name, instructor, rank
from tbl_training;
Thanks for the help in advance.

Answer 1

Try this code
select * from (
Select id_number, date_of_training, score, last_name, first_name, instructor, rank, row_number()over(partition by id_number order by date_of_training desc ) rn
from tbl_training)
where rn =1;