Concatenate many rows into a single text string - sql

Question

I'm trying to concatenate several names into a single column but I'm having trouble getting there.
DECLARE #Names VARCHAR(8000)
SELECT
p.Pato_Id
#Names = COALESCE(#Names + ', ', '') + e.First_Name + ' ' + e.Last_Name
FROM
Patos p
LEFT JOIN
Pato_Owners po
ON
po.Pato_Id = p.Pato_Id
LEFT JOIN
Person e
ON
po.Owner_Id = e.Person_Id
How can this be done?
EDIT:
When I'm making a normal select I getting
PatoID First Last
0 John Wort
0 Dan Mass
1 Till Bos
2 Wrap Sim
2 Port Lock
And what I want is:
PatoID Names
0 John Wort, Dan Mass
1 Till Bos
2 Wrap Sim, Port Lock

Answer 1

You have left join which indicate that you can have null names. This would reset the values of names should that occur.
;with cte as
(
SELECT
p.Pato_Id,
coalesce(e.First_Name, '') + coalesce(' ' + e.Last_Name, '') Name
FROM
Patos p
LEFT JOIN
Pato_Owners po
ON
po.Pato_Id = p.Pato_Id
LEFT JOIN
Person e
ON
po.Owner_Id = e.Person_Id
)
select t.Pato_id
,STUFF((
select ',' + [name]
from cte t1
where t1.Pato_Id = t.Pato_Id
for xml path(''), type
).value('.', 'varchar(max)'), 1, 1, '') [Names]
from cte t
group by t.Pato_id

Answer 2

Try this,
DECLARE #Names VARCHAR(8000)
SELECT
p.Pato_Id,
'ServerName' = COALESCE(#Names + ', ', '') + e.First_Name + ' ' + e.Last_Name
FROM
Patos p
LEFT JOIN
Pato_Owners po
ON
po.Pato_Id = p.Pato_Id
LEFT JOIN
Person e
ON
po.Owner_Id = e.Person_Id

Answer 3

I think you want this,
WITH Sales_CTE (Pato_Id, First, Last)
AS
(
Select p.Pato_Id , e.First , e.Last
FROM
Patos p
LEFT JOIN
Pato_Owners po
ON
po.Pato_Id = p.Pato_Id
LEFT JOIN
Person e
ON
po.Owner_Id = e.Person_Id
)
SELECT Pato_Id,
Substring((Select ',' + ISNULL(First,'') + ISNULL(Last,'') From Sales_CTE B Where B.Pato_Id=A.Pato_Id For XML Path('')),2,8000) As names
from Sales_CTE A group by Pato_Id;