joining on columns with null value

I have to join two tables. all of the columns can be null. However, if there are nulls and the rest of the fields are the same, I want to join to succeed.I did a test case where i assumed that if i used the following, I would get a record returned even if there are nulls. where nvl(tableA.column,0) = nvl(tableB.column,0)

If both of these fields are null and i have the rest of the columns equivalent, this will not give me a record returned.

However, if i do:

where tableA.column1||tableA.column2||tableA.column3 = tableB.column1||tableB.column2||tableB.column3

then i get a successful join if one or more of the fields is null but atleast 1 is not. this is pretty ugly. Any better way to do this?

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