Question

I hope someone can help, I’ve been trawling SO for hours and can’t find an answer that does what I need (or at least I can’t see how the answers apply to my situation)

So I have 3 tables, Horses, owners, and horse_owners

Table: horses
ID    Name    age
1     arkle   3
2     shergar 4
3     daisy   2

Table: owners
ID    Name   
1     Joe
2     Jack
3     Susan
4     Mike

Table: horse_owners
owner_id    horse_id
1           1
2           1
3           1
4           2

There are other fields but for the sake of simplicity I’ve removed them.
I want to run a query that lists the horses, and their owners (if they have any).

Here’s what I have now:

SELECT 
  h.id, 
  h.name, 
  h.age 
  GROUP_CONCAT(o.name separator ', ') as owners
FROM 
  horses h
LEFT JOIN 
  horse_owners ho 
ON 
  h.id = ho.horse_id
LEFT JOIN
  owners o
ON
  ho.owner_id = o.id

I’m using the group_concat function to combine the owners names where some have multiple owners. But the problem is the query only returns horses that have owners. I want to see all horses whether they have owners or not.

Answer 1

select 
  h.id, 
  h.name, 
  h.age,
  coalesce(group_concat(o.name order by o.name separator ', '),'Nobody') as owners
from 
  horses h
left join 
  horse_owners ho 
on 
  h.id = ho.horse_id
left join
  owners o
on
  ho.owner_id = o.id
 group by h.id