Row Number by Certain Column in SQL - sql

Question

I have a table that contains customer transactions. It looks like this:
Tha data is sorted by Total Transaction. I want to create a column that contains number by City. For Example, the first row shows City is London so the values is 1, second row becaus it's from London too, the value is also 1. When the Next Row is not London, the value is 2. So it looks like this:
Is there a way to create that row number in SQL Server?

Answer 1

You can try using dense_rank()
select *,dense_rank() over(order by city) as cityNumber
from tablename
order by total_transaction desc

Answer 2

I believe the question is valid and as per my understanding on the requirement , you need a two level of sub query to get to the final result,
Here I have used max as the data first has to be sorted by Total Transaction and then we can use dense_rank to give a row number using the max value and city.
select t.city as "City"
,dense_rank() over (order by max_total_per_city desc,city) as "City Number"
,t.customer as "Customer"
,t.total_transaction as "Total Transaction"
from
(
select *
,max(total_transaction) over (partition by city) as max_total_per_city
from tableName t
) t
order by total_transaction desc

Answer 3

You can get the CityNumbers with ROW_NUMBER() window function:
select City, row_number() over (order by max(TotalTransaction) desc) CityNumber
from tablename
group by City
so you can join the above query to the table:
select t.City, c.CityNumber, t.Customer, t.Totaltransaction
from tablename t inner join (
select City, row_number() over (order by max(TotalTransaction) desc) CityNumber
from tablename
group by City
) c on c.City = t.City
order by t.TotalTransaction desc
Or with DENSE_RANK() window function:
select t.City,
dense_rank() over (order by (select max(TotalTransaction) from tablename where City = t.City) desc) as cityNumber,
t.Customer,
t.TotalTransaction
from tablename t
order by t.TotalTransaction desc
See the demo.
Results:
> City | CityNumber | Customer | Totaltransaction
> :--------- | ---------: | :------- | ---------------:
> London | 1 | Michael | 250
> London | 1 | Edward | 180
> Paris | 2 | Michael | 160
> Madrid | 3 | Luis | 153
> London | 1 | Serena | 146
> Madrid | 3 | Lionel | 133
> Manchester | 4 | Frank | 96