update in sql

Question

i want to update pers_code and pers_name according to sno ..

sno pers_code pers_name

2 P0097871 A.ANNAMALAI

NULL NULL NULL

3 P0098263 A.B.PASARI

NULL NULL NULL

4 P0098275 A.C.SHAH

NULL NULL NULL

NULL NULL NULL

NULL NULL NULL

NULL NULL NULL