Question

The problem: I need to get values for X column with select statement, example:

People | X

————–

name1 | 1

name1 | 2

name1 | 3

name2 | 1

name2 | 2

name3 | 1

….

where people is unlimited count.

Answer 1

select 
  people,
  row_number() over(partition by people) as x
from yourtable

Update: Small feedback as summary of comments:
As Dave Costa and APC say, the results are non-deterministic. That is, if you run this query tomorow it is possible that first name1 to get id 2 in some conditions. However the query will still be correct.
If your table have attributes like DateInserted, DateOfBirth or other that can make a difference between same names, you can improve the query for example like this:

select 
  people,
  row_number() over(partition by people order by DateOfBirth) as x
from yourtable