Merging almost unique rows together
Assuming that each row in the source table only has either variable1, 2 or 3 populated, and there is only one such row for each combination, then this is probably the simplest approach:

SELECT Name, Column2, 
  MAX(Variable1),
  MAX(Variable2),
  MAX(Variable3)
FROM dbo.DataTable
GROUP BY Name, Column2;


SQLfiddle