How can I sum columns using conditions? - mysql

Question

I'm trying to do the sum when:
date_ini >= initial_date AND final_date <= date_expired
And if it is not in the range will show the last net_insurance from insurances
show last_insurance when is not in range
Here my tables:
POLICIES
ID POLICY_NUM DATE_INI DATE_EXPIRED TYPE_MONEY
1, 1234, "2013-01-01", "2014-01-01" , 1
2, 5678, "2013-02-01", "2014-02-01" , 1
3, 9123, "2013-03-01", "2014-03-01" , 1
4, 4567, "2013-04-01", "2014-04-01" , 1
5, 8912, "2013-05-01", "2014-05-01" , 2
6, 3456, "2013-06-01", "2014-06-01" , 2
7, 7891, "2013-07-01", "2014-07-01" , 2
8, 2345, "2013-08-01", "2014-08-01" , 2
INSURANCES
ID POLICY_ID INITIAL_DATE FINAL_DATE NET_INSURANCE
1, 1, "2013-01-01", "2014-01-01", 100
2, 1, "2013-01-01", "2014-01-01", 200
3, 1, "2013-01-01", "2014-01-01", 400
4, 2, "2011-01-01", "2012-01-01", 500
5, 2, "2013-01-01", "2014-01-01", 600
6, 3, "2013-01-01", "2014-01-01", 100
7, 4, "2013-01-01", "2014-01-01", 200
I should have
POLICY_NUM NET
1234 700
5678 600
9123 100
4567 200
Here is what i tried
SELECT p.policy_num AS policy_num,
CASE WHEN p.date_ini >= i.initial_date
THEN SUM(i.net_insurance)
ELSE (SELECT max(id) FROM insurances GROUP BY policy_id) END as net
FROM policies p
INNER JOIN insurances i ON p.id = i.policy_id AND p.date_ini >= i.initial_date
GROUP BY p.id
Here is my query http://sqlfiddle.com/#!2/f6077b/16
Somebody can help me with this please?
Is not working when is not in the range it would show my last_insurance instead of sum

Answer 1

Try it this way
SELECT p.policy_num, SUM(i.net_insurance) net_insurance
FROM policies p JOIN insurances i
ON p.id = i.policy_id
AND p.date_ini >= i.initial_date
AND p.date_expired <= i.final_date
GROUP BY i.policy_id, p.policy_num
UNION ALL
SELECT p.policy_num, i.net_insurance
FROM
(
SELECT MAX(i.id) id
FROM policies p JOIN insurances i
ON p.id = i.policy_id
AND (p.date_ini < i.initial_date
OR p.date_expired > i.final_date)
GROUP BY i.policy_id
) q JOIN insurances i
ON q.id = i.id JOIN policies p
ON i.policy_id = p.id
Output:
| POLICY_NUM | NET_INSURANCE |
|------------|---------------|
| 1234 | 700 |
| 5678 | 600 |
| 9123 | 100 |
| 4567 | 200 |
Here is SQLFiddle demo

Answer 2

This will ensure that you only get the last insurance if the policy has no insurances within the policy period.
SELECT policy_num, SUM(IF(p.cnt > 0, p.net_insurance, i.net_insurance)) AS net_insurance
FROM
(
SELECT
p.id,
p.policy_num,
SUM(IF(p.date_ini >= i.initial_date AND p.date_expired <= i.final_date,
i.net_insurance, 0)) AS net_insurance,
SUM(IF(p.date_ini >= i.initial_date AND p.date_expired <= i.final_date,
1, 0)) AS cnt,
MAX(IF(p.date_ini >= i.initial_date AND p.date_expired <= i.final_date,
0, i.id)) AS max_i_id
FROM policies p
INNER JOIN insurances i ON p.id = i.policy_id
GROUP BY p.id
) as p
LEFT JOIN insurances i ON i.id = p.max_i_id
GROUP BY p.id
Here is my SQLFiddle

Answer 3

Try splitting grouping from conditioning :)
SELECT
policy_num
, CASE
WHEN TRUE
AND p.date_ini <= src.initial_date
AND p.date_expired >= src.final_date
THEN src.sum_insurances
ELSE i.net_insurance
END AS something
FROM (
SELECT
max(id) AS latest_id
, sum(net_insurance) AS sum_insurances
, initial_date
, final_date
, policy_id
FROM insurances
GROUP BY policy_id
) src
JOIN policies p ON p.id = src.policy_id
JOIN insurances i ON i.id = src.latest_id
ORDER BY p.id