My database is like this 
no    name      age 
1      nan           23
2       nad          10
3       mam         10
4       rgh            10
5        hui            21
i want to add age which is  between the  no 2 to 4 
result will be 30 .
This is query to retrieve data between 2 to 4 
Select * from table where no between 2 and 4    but i dnt know how to add the age value ..please say query for this