How to get distinct values from database in gridview

Question

Hi
   I have one problem regarding gridview i,e follows:
        I wanna display values in gridview from database but not in dropdown list.
    Ex: I have one column(Item name) and it display redundant values like...

 Qty    Item Name     
  1       Petrol
  2       Petrol
  3       diesel 
  4       diesel     

But I want as like
Qty   Item Name
1      Petrol
2      diesel