How do I get the count of null value columns per row in a return set?

Question

I\'m looking for a query which will return me an extra column at the end of my current query which is the count of all columns within the return set which contain a null column.

Answer 1

As in a similar post, SQL is not very suited to work across different columns within a row, but muach better on working across rows.

I'd suggest to turn the table into 'individual' facts about a row, e.g.

select , col1 as value From aTable
UNION
select , col2 as value From aTable
UNION
... and so on for the other columns to be summed.

This can be turned into a view i.e.

create view aView as (select as above).

Then the correct answer is just

select key, count(*)
from aView
where value is null
Group By key