How to sum all titles even others are empty - mysql

Question

my query objective is to sum all the fields from (3) tables but i have some problem in generating the final_total_sum output if some of the other titles empty the final_total_sum is empty....but if all titles are not empty my query generate final_total_sum(output).
I wan to do is even other titles are empty my query can still generate a final_total_sum(output).
http://s38.photobucket.com/user/eloginko/media/output_zpsfcab9d54.png.html
current query:
SELECT *,
ROUND(interview_sum +
other_sum +
edu_attain2_sum +
experience2_sum +
trainings2_sum +
eligibility2_sum) AS final_total_sum
FROM (
SELECT
ROUND((SELECT SUM(t2.inttotal)
FROM app_interview2 AS t2
WHERE t2.atic = t.atic)/7,1)
AS interview_sum,
ROUND((SELECT SUM(o2.ototal)
FROM other_app2 AS o2
WHERE o2.oaic = t.atic)/7,1)
AS other_sum,
ROUND((SELECT SUM(s1.edu_attain2)
FROM qual_stan2 AS s1
WHERE s1.oaic2 = t.atic)/7,1)
AS edu_attain2_sum,
ROUND((SELECT SUM(s2.experience2)
FROM qual_stan2 AS s2
WHERE s2.oaic2 = t.atic)/7,1)
AS experience2_sum,
ROUND((SELECT SUM(s3.trainings2)
FROM qual_stan2 AS s3
WHERE s3.oaic2 = t.atic)/7,1)
AS trainings2_sum,
ROUND((SELECT SUM(s4.eligibility2)
FROM qual_stan2 AS s4
WHERE s4.oaic2 = t.atic)/7,1)
AS eligibility2_sum,
t.atid,
t.atic,
t.atname,
t.region,
t.town,
t.uniq_id,
t.position,
t.salary_grade,
t.salary
FROM app_interview2 AS t
WHERE uniq_id = '$q'
GROUP BY t.atname
HAVING COUNT(DISTINCT t.atic)) subq

Answer 1

Try:
ROUND( ifnull(interview_sum,0) +
ifnull(other_sum,0) +
ifnull(edu_attain2_sum,0) +
ifnull(experience2_sum,0) +
ifnull(trainings2_sum,0) +
ifnull(eligibility2_sum,0)) AS final_total_sum
In SQL x + NULL always gives NULL, ifnull function converts nulls to 0

Answer 2

use like SUM(ifnull(t2.inttotal,0))