Specific Group By query in SQL Server

Question

initial table:

 1   1   3
 1   1   4
 1   2   1
 1   2   3
 2   1   5
 2   1   2
 2   2   2
 2   2   3

after group by on third column and sum on that column:

 1   1   7
 1   2   4
 2   1   7
 2   2   5

Answer 1

SELECT Col1, Col2, SUM(Col3)
FROM dbo.YourTable
GROUP BY Col1, Col2

Something like that??

Answer 2

Specify multiple columns to group by and it will only group when the values in all the columns are the same:

SELECT ColA, ColB, Sum(ColC) as Summation
FROM YourTable
GROUP BY ColA, ColB