DB2 Query multiple select and sum by date - db2

Question

I have 3 tables: ITEMS, ODETAILS, OHIST.
ITEMS - a list of products, ID is the key field
ODETAILS - line items of every order, no key field
OHIST - a view showing last years order totals by month
ITEMS ODETAILS OHIST
+----+----------+ +-----+---------+---------+----------+ +---------+-------+
| ID | NAME | | OID | ODUE | ITEM_ID | ITEM_QTY | | ITEM_ID | M5QTY |
+----+----------+ +-----+---------+---------+----------+ +---------+-------+
| 10 + Widget10 | | A33 | 1180503 | 10 | 100 | | 10 | 1000 |
+----+----------+ +-----+---------+---------+----------+ +---------+-------+
| 11 + Widget11 | | A33 | 1180504 | 11 | 215 | | 11 | 1500 |
+----+----------+ +-----+---------+---------+----------+ +---------+-------+
| 12 + Widget12 | | A34 | 1180505 | 10 | 500 | | 12 | 2251 |
+----+----------+ +-----+---------+---------+----------+ +---------+-------+
| 13 + Widget13 | | A34 | 1180504 | 11 | 320 | | 13 | 4334 |
+----+----------+ +-----+---------+---------+----------+ +---------+-------+
| A34 | 1180504 | 12 | 450 |
+-----+---------+---------+----------+
| A34 | 1180505 | 13 | 125 |
+-----+---------+---------+----------+
Assuming today is May 2, 2018 (1180502).
I want my results to show ID, NAME, M5QTY, and SUM(ITEM_QTY) grouped by day
over the next 3 days (D1, D2, D3)
Desired Result
+----+----------+--------+------+------+------+
| ID | NAME | M5QTY | D1 | D2 | D3 |
+----+----------+--------+------+------+------+
| 10 | Widget10 | 1000 | 100 | | 500 |
+----+----------+--------+------+------+------+
| 11 | Widget11 | 1500 | | 535 | |
+----+----------+--------+------+------+------+
| 12 | Widget12 | 2251 | | 450 | |
+----+----------+--------+------+------+------+
| 13 | Widget13 | 4334 | | | 125 |
+----+----------+--------+------+------+------+
This is how I convert ODUE to a date
DATE(concat(concat(concat(substr(char((ODETAILS.ODUE-1000000)[phone]),1,4),'-'), concat(substr(char((ODETAILS.ODUE-1000000)[phone]),5,2), '-')), substr(char((ODETAILS.ODUE-1000000)[phone]),7,2)))

Answer 1

Try this (you can add the joins you need)
SELECT ITEM_ID
, SUM(CASE WHEN ODUE = INT(CURRENT DATE) - 19000000 + 1 THEN ITEM_QTY ELSE 0 END) AS D1
, SUM(CASE WHEN ODUE = INT(CURRENT DATE) - 19000000 + 2 THEN ITEM_QTY ELSE 0 END) AS D2
, SUM(CASE WHEN ODUE = INT(CURRENT DATE) - 19000000 + 3 THEN ITEM_QTY ELSE 0 END) AS D3
FROM
ODETAILS
GROUP BY
ITEM_ID