T-SQL query to fetch row with multiple aggregate functions - sql

Question

I have the following problem. I need to fetch the row for each distinct user_id with the min rank, max end date, max begin date, and max sequence number in that order. Essentially, I want a user's highest ranked, most recent MAJOR_ID. I am trying to avoid making separate temp tables and joining on those aggregate functions like the following:
select USER_ID
, SEQ_NBR
, BEGIN_DATE
, END_DATE
, MAJOR_RANK
, MAJOR_ID
, DEGREE_CODE
into #major0
from majors
select USER_ID
, MIN(MAJOR_RANK) as MAJOR_RANK
into #major1
from #major0
group by USER_ID
select #major0.USER_ID
, #major0.MAJOR_RANK
, MAX(#major0.END_DATE) as END_DATE
into #major2
from #major0
inner join #major1 on #major0.USER_ID = #major1.USER_ID and #major0.MAJOR_RANK = #major1.MAJOR_RANK
group by #major0.USER_ID
, #major0.MAJOR_RANK
etc...
until I get to that row that satisfies all the criteria, and I join back on all the fields from the original query. Does that make sense? It's a lot of work to write this out, and I can't create a view of it unless I made a absurdly long set of subqueries, I don't think I can utilize MIN(MAJOR_RANK) OVER (PARTITION BY USER_ID) in a subquery for all these fields because I will lose records that don't satisfy all of them.
Any suggestions would help! Thank you!

Answer 1

I do not see what the sequence_number is, but you can most likely solve this using a common table expression with row_number()
;with cte as (
select
user_id
, begin_date
, end_date
, major_rank
, major_id
, degree_code
, rn = row_number() over (
partition by user_id
order by major_rank asc, end_date desc, begin_date desc /*, sequence_number? desc*/
)
from majors
)
select
user_id
, begin_date
, end_date
, major_rank
, major_id
, degree_code
from cte
where rn = 1
without the cte
select
user_id
, begin_date
, end_date
, major_rank
, major_id
, degree_code
from (
select
user_id
, begin_date
, end_date
, major_rank
, major_id
, degree_code
, rn = row_number() over (
partition by user_id
order by major_rank asc, end_date desc, begin_date desc /*, sequence_number? desc*/
)
from majors
) sub
where rn = 1