如何在一个 mysql 查询中从一个表中获取值以及从另一个连接表中获取值数组？

Question

I have a table called lists and a join table called items_to_lists .

I want to query and return all lists for a particular user:

SELECT lists.* FROM lists WHERE lists.user_id = 'someUserID'

But I also want to include in this query all of the item_id values in the join table as an array for each list. Is this possible? What I want to be returned is:

list_id = ... , user_id = ... [deck_id1, deck_id2, etc] for each list.

What I have tried is:

SELECT lists.*, items_to_lists.item_id FROM lists INNER JOIN items_to_lists ON items_to_lists.list_id = lists.list_id WHERE lists.user_id = 'someUserID'

This returns each relation as a separate row rather than an array associated with each list. Is there anyway to return the list row with an array of the join table item_id's?

Answer 1

GROUP_CONCAT has some more Options like choosing the SEPERAOTR or Ordering the ids

SELECT l.*, CONCAT('[',GROUP_CONCAT(DISTINCT il.item_id) ,']')
FROM lists l INNER JOIN items_to_lists il ON il.list_id = l.list_id 
WHERE l.user_id = 'someUserID'

Answer 2

You could use GROUP_CONCAT with GROUP BY , something like this:

SELECT
  lists.list_id, GROUP_CONCAT(items_to_lists.item_id)
FROM lists INNER JOIN items_to_lists ON items_to_lists.list_id = lists.list_id
WHERE
  lists.user_id = 'someUserID'
GROUP BY
  lists.list_id