Enumerate and add in a column of the select - Oracle

Question

I need to enumerate my lines in a column of the select by a type. For example, I have three types which can be "RR", "RJ" and "RA", every time that a type "RR" appears I have to sum 3 and the other ones I have to sum only 1, creating a sequence like:

Type Number
RR 3
RR 6
RJ 7
RR 10
RJ 11
RA 12
RR 15

I have other fields in the select, so I used the ROW_NUMBER() function with all my order by fields, something like:

select
   number,
   [...]
   type,
   ROW_NUMBER() OVER (order by number, type [...] )*3 as sequence
from
   my_table
order by number, type [...] 

I also tried to use a case statement, but it doesn't aggregate the values.

Is it possible to do? I'm trying to use the ROW_NUMBER() function, but i can't get the result, only three by three.

Answer 1

You could use SUM:

select
   number,
   [...]
   type,
   SUM(CASE WHEN Type = 'RR' THEN 3 ELSE 1 END) 
       OVER (order by number, type [...] ) as sequence
from my_table
order by number, type [...] 

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