SQL count specific value over multiple columns and rows

Question

I feel as if this should be quite easy, but can\'t seem to find a solution. Suppose I have the following table:

|--------||---||---||---||---||---||---||---|         


        

Answer 1

Not so easy, each column needs to be hard-coded. I'd try something using a CASE or DECODE.

SELECT 
SUM(
CASE WHEN q1 = 1 THEN 1 ELSE 0 END +
CASE WHEN q2 = 1 THEN 1 ELSE 0 END +
CASE WHEN q3 = 1 THEN 1 ELSE 0 END +
CASE WHEN q4 = 1 THEN 1 ELSE 0 END +
CASE WHEN q5 = 1 THEN 1 ELSE 0 END +
CASE WHEN q6 = 1 THEN 1 ELSE 0 END +
CASE WHEN q7 = 1 THEN 1 ELSE 0 END)
FROM table
WHERE Company = 'abc'

Using a SUM instead of a COUNT will allow the CASE statement to be SUMed.

Answer 2

For reasons of efficiency I don't recommend actually using this approach; but for learning purposes here's another way you could have broken down the problem along the lines of the way you were thinking about it.

select sum(c) as total_ones
from
    (
    select count(*) c from table where q1 = 1 union all
    select count(*)   from table where q2 = 1 union all
    select count(*)   from table where q3 = 1 union all
    select count(*)   from table where q4 = 1 union all
    select count(*)   from table where q5 = 1 union all
    select count(*)   from table where q6 = 1 union all
    select count(*)   from table where q7 = 1
    ) t

Answer 3

This is very weird assignment but:

http://sqlfiddle.com/#!9/2e7aa/3

SELECT SUM((q1='1')+(q2='1')+(q3='1')+(q4='1')+(q5='1')+(q6='1')+(q7='1')) 
FROM table
WHERE Company = 'abc'
AND '1' IN (q1,q2,q3,q4,q5,q6,q7)

Answer 4

SELECT SUM(
    IF(q1 = 1, 1, 0) +
    IF(q2 = 1, 1, 0) +
    IF(q3 = 1, 1, 0) +
    IF(q4 = 1, 1, 0) +
    IF(q5 = 1, 1, 0) +
    IF(q6 = 1, 1, 0) +
    IF(q7 = 1, 1, 0)
)
FROM table
WHERE Company = 'abc'

Answer 5

Use conditional COUNT

SELECT COUNT(case when q1 = '1' then 1 end)  + 
       COUNT(case when q2 = '1' then 1 end)  + 
       COUNT(case when q3 = '1' then 1 end)  + 
       COUNT(case when q4 = '1' then 1 end)  + 
       COUNT(case when q5 = '1' then 1 end)  + 
       COUNT(case when q6 = '1' then 1 end)  + 
       COUNT(case when q7 = '1' then 1 end) as ones_total
FROM table
WHERE Company = 'abc'