To generate sequential numbers on the fly using inner join

Declare @t Table(Name Varchar(20),Age int)
Insert Into @t 
Select 'Name1', 20 Union All Select 'Name2', 21 Union All 
Select 'Name3', 22 Union All Select 'Name4', 23 Union All
Select 'Name5', 24

Select
	Rn = COUNT(*) 
	,t1.Name
	,t1.Age
From @t t1
Join @t t2 On  t1.Name >= t2.Name
Group By t1.Name,t1.Age
Order By  t1.Name,t1.Age

/* Result */
Rn	Name	Age
1	Name1	20
2	Name2	21
3	Name3	22
4	Name4	23
5	Name5	24