Help with COUNT across multiple columns
Given the new information (you should probably edit the question, not add an answer, but I assume you are not entitled to). First I don't understand the database design, do you always get 4 affected devices per fault? Anyhow, you can transpose your table like:

select affected_device_1 from faults
union all
select affected_device_2 from faults
union all
select affected_device_3 from faults
union all
select affected_device_4 from faults


I won't be efficient but it is the best I can think of. From there you can count the number of occurrences for each device:

select affected_device, count(1)
from (
    select affected_device_1 as affected_device from faults
    union all
    select affected_device_2 as affected_device from faults
    union all
    select affected_device_3 as affected_device from faults
    union all
    select affected_device_4 as affected_device from faults
) as T
group by affected_device;


Note that if a fault contains the same device twice the count will be wrong.