star rating system get top 10 records

[eluser]harman[/eluser]
hi please help me in this problem it's not CI related its General SQL please help me to over come this problem

i am creating star rating system i can calculate the total votes, avg. rating but now i need top rated 10 items how can i calculate rating weight-age : here is my db table

Code:

id   rating     product_id
1    5          120    
2    2          120    
3    2          120
4    4          25    
5    5          25

in short: can anybody provide me SQL query to calculate top 10 rated items