select isnull(column1,'')+','+isnull(column2,'')+','+isnull(column3,'') AS column4 from table
From the above query, I am getting what I need, which is really good. But the thing here is if all the columns all NULL I am getting commas which I have used to separate the fields.
I want comma is to be replaced with NULL when every field is NULL. Can anyone help me in this? thank you!