如何在 MYSQL 上合并来自 GROUP_CONCAT 的相同结果

Question

now im doing some query using GROUP_CONCAT on mysql. for example

i have table "sales_orders"

+----------+----------+------------+
| order_id | quantity | product_id |
+----------+----------+------------+
| 1        | 1        |         101|
| 1        | 1        |         102|
| 2        | 1        |         103|
| 2        | 1        |         104|
| 3        | 1        |         101|
| 3        | 1        |         102|
+--------+------------+------------+

my query like this

SELECT order_id, count(quantity) AS qty, GROUP_CONCAT(DISTINCT product_id ORDER BY product_id ASC ) AS product_id FROM sales_orders GROUP BY order_id

and the output like this

+----------+-----+------------+
| order_id | qty | product_id |
+----------+-----+------------+
|         1|    2|101,102     |
|         2|    2|103,104     |
|         3|    2|101,102     |
+----------+-----+------------+

if we see, product_id have same result for 101,102 . how do i can manage to merge that same result become like this with count for qty also.

+-----+------------+
| qty | product_id |
+-----+------------+
|    4|101,102     |
|    2|103,104     | 
+-----+------------+

maybe order_id for me is not important to display. please help

Answer 1

First observation of mine is that the quantity may at times be more than 1. For that reason I would suggest use sum instead of count for quantity

Next query using a sub-query.

SELECT sum(qty) AS quantity, product_id FROM (SELECT order_id, sum(quantity) AS qty, GROUP_CONCAT(DISTINCT product_id ORDER BY product_id ASC ) AS product_id FROM sales_orders GROUP BY order_id) as derived_table GROUP BY product_id