I'm looking for an efficient approach where I can assign numbers in sequence to each group.
Record Group GroupSequence
-------|---------|--------------
1 Car 1
2 Car 2
3 Bike 1
4 Bus 1
5 Bus 2
6 Bus 3
I came through this question: How to add sequence number for groups in a SQL query without temp tables. But my use case is slightly different from it. Any ideas on how to accomplish this with a single query?
You are looking for row_number():
select t.*, row_number() over (partition by group order by record) as group_sequence
from t;
You can calculate this when you need it, so I see no reason to store it. However, you can update the values if you like:
update t
set group_sequence = tt.new_group_sequence
from (select t.*,
row_number() over (partition by group order by record) as new_group_sequence
from t
) tt
where tt.record = t.record;
