Query SUM mysql with if condition - mysql

Question

I have some table in mysql database like this.
id | product | warehouse | price | date_shipping
------------------------------------------------
1 | Salt | 15 | 300 | 2017-03-08
2 | Salt | 15 | 300 | 2017-03-09
I want to SUM that column price with several condition. This is the condition.
From the product salt if the warehouse is have same id I don't want to SUM price value.
This is my second condition.
id | product | warehouse | price | date_shipping
------------------------------------------------
1 | Salt | 15 | 300 | 2017-03-08
2 | Salt | 18 | 300 | 2017-03-09
From the product salt if the warehouse is have different id I want to SUM price value.
This is the result what I want from the query.
From first condition :
salt | 15 | 300
From second condition :
salt | 15,18 | 600
This is query what I have doing.
SELECT product, GROUP_CONCAT(warehouse SEPARATOR ',') as warehouse, SUM(price)
FROM db_product
Somebody can help me with this ? Thank you.

Answer 1

Your problem requires two aggregations. The first one identifies, for each product in a warehouse, the record having the earliest shipping date. Then, a second aggregation is needed to group concatenate the warehouses for each product.
SELECT t.product,
GROUP_CONCAT(t.warehouse) AS warehouses,
SUM(t.price) AS total
FROM
(
SELECT t1.product,
t1.warehouse,
t1.price
FROM db_product t1
INNER JOIN
(
SELECT product, warehouse, MIN(date_shipping) AS min_date_shipping
FROM db_product
GROUP BY product, warehouse
) t2
ON t1.product = t2.product AND
t1.warehouse = t2.warehouse AND
t1.date_shipping = t2.min_date_shipping
) t
GROUP BY t.product
Output:
Demo here:
Rextester