Subquery using result from parent query - mysql

Question

UPDATE The pay query is now solved with the help provided in the replies. The answer Strawberry provided is very close. It just needed to be edited a bit as the WHERE clause has a redundancy and incorrect statement that I provided in my original query. Here is the correct, slightly revised query:
SELECT ux.user_id
, ux.meta_value pay
FROM wp_um_groups_members m
Join wp_usermeta ux
ON m.user_id1 = ux.user_id
WHERE ux.meta_key = CONCAT('_um_groups_', m.group_id,'_price')
This matches the following data for my 'Pay' field:
From up_usermeta:
umeta_id | user_id | meta_key | meta_value
===========================================================
622680 | 5989 | _um_groups_47652_price | 500
From wp_um_groups_members:
id | group_id | user_id1 | user_id2 | status | role | invites | time_stamp | date_joined
===============================================================================================================
187 | 47682 | 5989 | 3 | approved | member | 1 | 2020-02-15 10:59:08 | 2020-02-15 10:59:08
I through that in with my original query below, and everything is working.
Original Post
I'm sure I'm making this much more difficult than it needs to be. Below is the flow chart and query. When I add the 'Pay'subquery, I receive results that are not matched correctly. If I remove the "Pay" subquery, it works fine (with exception that there is no pay).
In the database, I have many entries in wp_usermeta.meta_value such as:
meta_value = _um_groups_47859_price
In that example, the number 47859 equals the value of wp_um_groups_members.group_id
So I was hoping to be able to query that exact match using something similar to: LIKE CONCAT('%', wp_um_groups_members.group_id ,'%')
That did not seem to work either.
Here is my current query:
SELECT
wp_um_groups_members.group_id AS ID, wp_posts.post_title AS Gig, Location.Location, Type.`Event Type`, wp_users.display_name AS Player, Date.Date, Pay.Pay
FROM
wp_um_groups_members
Inner Join wp_posts ON
wp_um_groups_members.group_id = wp_posts.ID
Inner Join (SELECT
wp_postmeta.post_id, wp_postmeta.meta_value AS Location
FROM
wp_postmeta
WHERE
wp_postmeta.meta_key = '_um_groups_event_location'
) Location ON
Location.post_id = wp_posts.ID
Inner Join (SELECT
wp_postmeta.post_id, wp_postmeta.meta_value AS `Event Type`
FROM
wp_postmeta
WHERE
wp_postmeta.meta_key = '_um_groups_event_type'
) Type ON
Type.post_id = wp_posts.ID
Inner Join wp_users ON
wp_users.ID = wp_um_groups_members.user_id1
Inner Join (SELECT
wp_postmeta.post_id, wp_postmeta.meta_value AS Date
FROM
wp_postmeta
WHERE
wp_postmeta.meta_key = '_um_groups_event_start'
) Date ON
Date.post_id = wp_posts.ID
Inner Join (SELECT
wp_usermeta.user_id, wp_usermeta.meta_value AS Pay
FROM
wp_um_groups_members
Inner Join wp_usermeta ON
wp_um_groups_members.user_id1 = wp_usermeta.user_id
WHERE
wp_usermeta.meta_key like '%price'
) Pay ON
Pay.user_id = wp_users.ID
WHERE
wp_um_groups_members.status = 'approved'
Is there a way to to modify that last Inner Join in order to contain something like: WHERE
wp_usermeta.meta_value = '_um_groups_47859_price' in which 47859 would is wp_um_groups_members.group_id?

Answer 1

SELECT ux.user_id
, ux.meta_value pay
FROM wp_um_groups_members m
Join wp_usermeta ux
ON m.user_id1 = ux.user_id
WHERE ux.meta_key LIKE '%price'
AND ux.meta_value = CONCAT('_um_groups_', m.group_id,'_price')
Incidentally, while there's no performance benefit, when working with an EAV (like wp_postmeta), I prefer this syntax...
SELECT post_id
, MAX(CASE WHEN meta_key = '_um_groups_event_location' THEN meta_value END) location
, MAX(CASE WHEN meta_key = '_um_groups_event_type' THEN meta_value END) event_type
, MAX(CASE WHEN meta_key = '_um_groups_event_start' THEN meta_value END) date
, MAX(CASE WHEN meta_key = '_um_groups_event_type' THEN meta_value END) event_type
FROM wp_postmeta
GROUP
BY post_id
(Strictly speaking, this is more akin to using LEFT JOIN than INNER JOIN, as per your example)