Sort null values of one column by another

amitchandak  mussaenda 

I am using visual matrix so I have 3 files in Row section.

Category A

Category A1

Category A1.1

Category A1.2

Category A2

Category A2.1

Category A2.2

Category B

Category B1

Category B1.1

Category B1.2

Category B2

Category B2.1

Category B2.2 and so on as 10 Categories total.

Now category A, B, C, etc. cannot be empty, but category A1, A2, B1, B2 can be empty. Category A1.1 A1.2 B1.1 B1.2 etc. it can never be empty.

Now the problem is when A1 A2 B1 B2 etc are empty, but your sub catering is not empty. I can't sort them in order.

when I try to sort my 2nd category column by 3rd category coulumn it doesn't allow me to sort the data because 2nd category has a lot of null values, but 3rd category has no NULL values. So when I order it, it gives the error "2nd Category cannot be sorted by 3rd, because 3rd Category cannot have multiple values ​​for the same 2nd Category value" ...

So the question is, how can I sort the null values ​​in one column based on the values ​​in another column ... For every null value, there is a difference value in another column