SQL Count empty fields

Question

I'm not sure if this is possible or if it is, how to do it -

I have the following data in a database -

id     |    improve |   timeframe |  criteria |  impact
-------+------------+-------------+-----------+--------- 
1      |            |    Test     |   Test    |    Test
2      |    Test    |             |   Test    |   
3      |            |    Test     |           |    
-------+------------+-------------+-----------+--------- 

Ignoring the id column, how can I determine the number of fields out of the remaining 12 that are not null using an SQL query?

I have started with -

SELECT improve, timeframe, impact, criteria 
FROM data 
WHERE improve IS NOT NULL 
  AND timeframe IS NOT NULL 
  AND impact IS NOT NULL 
  AND criteria IS NOT NULL;

This only returns the number of rows, ie. 3.

Any ideas?

Thanks.

Solution 1

SELECT count(improve) + count(timeframe) + count(impact) + count(criteria) FROM data 

Solution 2

Something like this may get you going in the right direction

SELECT 
SUM(CASE WHEN improve IS NULL THEN 0 ELSE 1 END +
CASE WHEN timeframe IS NULL THEN  0 ELSE 1 END +
CASE WHEN criteria IS NULL THEN  0 ELSE 1 END +
CASE WHEN impact IS NULL THEN  0 ELSE 1 END)
from
data