MYSQL - Count of similar results from a group_concat

Question

I have the following table:

product_ID | detail_ID
15228 | 1
19450 | 1
21309 | 336
21309 | 425
21310 | 336
26415 | 148
28842 | 497
53443 | 1

And I am currently running the following query:

SELECT product_ID, GROUP_CONCAT(DISTINCT detail_ID separator ', ') AS detailIds
FROM productdetails
GROUP BY product_ID

this query gives me the following results:

product_ID | detailIds
15228      | 1
19450      | 1
21309      | 336, 425
21310      | 336
26415      | 148
28842      | 497
53443      | 1

What I would like to return is:

group_concat on product_ID | group_concat | count of group_concat
15228, 19450, 53443        | 1            | 3
21309                      | 336, 425     | 1
21310                      | 336          | 1
26415                      | 148          | 1
28842                      | 497          | 1

I have tried to use aggregate functions like count on the group_concat and group_concat on group_concat but mysql is very unhappy with these attempts. Any suggestions, would be greatly appreciated!

I am trying to do this in MySQL.

The goal is to find products with similar features and then to see how often these similar features are appearing. Thanks!

Answer 1

Use your query as a subquery and do another group_concat() :

SELECT GROUP_CONCAT(product_ID) as Products, detailIds, count(*) as NumProducts
FROM (SELECT product_ID, GROUP_CONCAT(DISTINCT detail_ID separator ', ') AS detailIds
      FROM productdetails
      GROUP BY product_ID
     ) P
GROUP BY detailIds;