add sno coloum and row sno in sql table

Question

add sno 1 to end of the coloum 

i have table like ...
400000 laks rows  in my table 

name   address      id    location
raju     hyd         6789    hyd
vamshi   vizag      9876   hashinapur

o/p like
i want insert sno coloum and sno 1 to 400000

sno      name          address       id      location   
1          raju             hyd          6789      hyd
2        vamshi          vizag        9876     hasthinapur  
3
4
5
6
..
.
.
.
.
40000