Here's my dataset
Id Column_A Column_B Column_C
1 Null 7 Null
2 8 7 Null
3 Null 8 7
4 8 Null 8
If at least one column is null, Combination will be Null
Id Column_A Column_B Column_C Combination
1 Null 7 Null Null
2 8 7 Null Null
3 Null 8 7 Null
4 8 Null 8 Null