每月给出每个行号-Oracle SQL

Question

I have a table like this:

Month     | Date   
----------------------
May 2019  | 03.05.19
May 2019  | 04.05.19 
May 2019  | 07.05.19   
July 2019 | 03.07.19
July 2019 | 05.07.19 
July 2019 | 06.07.19  
July 2019 | 08.07.19 

And I wanna have a query that gives out the following.

Month     | Date    | Row Count per Month
----------------------
May 2019  | 03.05.19 | 1
May 2019  | 04.05.19 | 2
May 2019  | 07.05.19 | 3
July 2019 | 03.07.19 | 1
July 2019 | 05.07.19 | 2
July 2019 | 06.07.19 | 3
July 2019 | 08.07.19 | 4

So it gives out the number of each row per month but I don't know how to do it ( I have many more months and dates than those). I am trying to do it with row_number but can't seem to get it right. Any tips?

Answer 1

Use row_number()

select *,row_number() over(partition by month order by date) as Row_Count
from tablename

Answer 2

使用row_number()

   select t.*, row_number() over( partition by month order by date) rn from table t