SQL Query

I have a table (Tab1) with two columns (C1 & C2)

C1 has values 1,1,1,2,2

C2 has values 1,2,3,4,5

I want to query to display value of C1 just once and all the values of C2 

EX:

C1C2

11

2

3

24

5

Can someone help