MySQL group_concat with select inside select - mysql

Question

I have a glitch which i cannot solve,let me elaborate...
These are my MySQL tables...
Therapists table
id therapist_name
1 Therapist 1
2 Therapist 2
Location table
+-----+------------+--+
| id | name | |
+-----+------------+--+
| 1 | Location 1 | |
| 2 | Location 2 | |
| 3 | Location 3 | |
+-----+------------+--+
Days_location table
+-----+-----------+--------------+-------------+--+
| id | day | therapist_id | location_id | |
+-----+-----------+--------------+-------------+--+
| 1 | monday | 1 | 1 | |
| 2 | monday | 1 | 2 | |
| 3 | wednesday | 1 | 3 | |
| 4 | wednesday | 2 | 1 | |
| 5 | tuesday | 2 | 2 | |
| 6 | friday | 2 | 1 | |
| 7 | friday | 2 | 2 | |
| 8 | friday | 1 | 1 | |
+-----+-----------+--------------+-------------+--+
Now i want to get every therapist with locations for every day,for example something like this:
therapist_name=>Therapist 1,day_locations=>monday(Location1,Location2),friday(Location1)
I need it to be as a select variable,this was my query but i got stuck there:
SELECT t.*,GROUP_CONCAT(
SELECT CONCAT(dl2.day,GROUP_CONCAT(dl2.location_id)) as concated
FROM days_location dl2
WHERE therapist_id=85
GROUP BY dl2.day
) as day_location
FROM therapists t
LEFT JOIN days_location dl
ON dl.therapist_id=t.id
This of course doesn't work,what am i doing wrong...should i try a different approach or make my tables different?

Answer 1

I believe this is what you're looking for, or could get you started:
SELECT
t.therapist_name,
dl.day,
GROUP_CONCAT(DISTINCT dl.name SEPARATOR ',') AS locations
FROM
therapists t
LEFT JOIN days_location dl ON dl.therapist_id = t.id
LEFT JOIN location l ON dl.location_id = l.id
GROUP BY t.therapist_name, dl.day
For therapists.id = 1 this should give you results:
+----------------+-----------+-----------------------+
| therapist_name | day | locations |
+----------------+-----------+-----------------------+
| Therapist 1 | monday | Location 1,Location 2 |
| Therapist 1 | wednesday | Location 3 |
| Therapist 1 | friday | Location 1 |
+----------------+-----------+-----------------------+
If you need to concatenate day with locations column then use a simple CONCAT():
SELECT
therapist_name,
CONCAT(day, '(', locations, ')') AS locations
FROM (
SELECT
t.therapist_name,
dl.day,
GROUP_CONCAT(DISTINCT dl.name SEPARATOR ',') AS locations
FROM
therapists t
LEFT JOIN days_location dl ON dl.therapist_id = t.id
LEFT JOIN location l ON dl.location_id = l.id
GROUP BY t.therapist_name, dl.day
) t
GROUP BY therapist_name, locations
Output should look like:
+----------------+-------------------------------+
| therapist_name | locations |
+----------------+-------------------------------+
| Therapist 1 | monday(Location 1,Location 2) |
| Therapist 1 | wednesday(Location 3) |
| Therapist 1 | friday(Location 1) |
+----------------+-------------------------------+
If you need to group it all into one row for each therapist, then you could GROUP_CONCAT() again.
Edit after comments:
SELECT
therapist_name,
GROUP_CONCAT( CONCAT(day, '(', locations, ')') SEPARATOR ',' ) AS locations
FROM (
SELECT
t.therapist_name,
dl.day,
GROUP_CONCAT(DISTINCT dl.name SEPARATOR ',') AS locations
FROM
therapists t
LEFT JOIN days_location dl ON dl.therapist_id = t.id
LEFT JOIN location l ON dl.location_id = l.id
GROUP BY t.therapist_name, dl.day
) t
GROUP BY therapist_name
I haven't tested the code so there may be some minor mistakes to tweak. No way of testing it atm.