How to generate SQL output with pipes with multiple tables - sql

Question

I am using SQL Server.
I have a table of students like this:
StudentID TeacherNumber
123 1
124 1
125 2
126 2
127 1
128 3
I also have a table of teachers like this:
TeacherNumber TeacherName
1 Adams
2 Johnson
3 Marks
I need to have output that looks like this:
TeacherNumber Teacher Students
1 Adams 123|124|127
2 Johnson 125|126
3 Marks 128
I appreciate your help. Thank you.
I posted a similar question previously, and got a response that worked here:
How to generate sql output as piped
Now that I added another table I am having trouble. I appreciate the help.

Answer 1

Fiddle:
http://sqlfiddle.com/#!6/27600/29/0
Query:
select distinct st1.teachernumber,
teachername as teacher,
stuff(( select '|' + cast(st2.studentid as varchar(20))
from students st2
where st1.teachernumber = st2.teachernumber
order by st2.studentid
for xml path('')
),1,1,'') as students
from students st1
join teachers t
on st1.teachernumber = t.teachernumber
The reason I had to convert STUDENTID to VARCHAR is because by adding the pipe character that data type would no longer be valid and you'd get an error. You have to cast it as varchar to get the pipe delimiter to work with an integer field (I assume STUDENTID is an INT field).
Output:
| TEACHERNUMBER | TEACHER | STUDENTS |
|---------------|---------|-------------|
| 1 | Adams | 123|124|127 |
| 2 | Johnson | 125|126 |
| 3 | Marks | 128 |