Oracle: Finding Columns with only null values

Question

I have a table with a lot of columns and a type column.

Some columns seem to be always empty for a specific type.

I want to create a view for each type and o

Answer 1

You can identify by using the below query :

select * from (select ascii(t.col2)+ascii(t.col4)+ascii(t.col1)+ascii(t.col3) col from test_null_col t)
where col is null;

And you want to delete null column rows here is query :

delete from
(select ascii(t.col2)+ascii(t.col4)+ascii(t.col1)+ascii(t.col3) col from test_null_col t)
where col is null;