Query everything that comes after the '#' - sql

Question

I am setting up a new query but unfortunately I got stuck in some kind of functions in SQL. I have some records with specific emails. All I want is bringing everything that comes after the '#'.
For example:
cesarcastillo88#hotmail.com ==> as a result I should get the following: hotmail.com.
This was not complicated at all because of the fact that the record shows one email only.
But...what if that record includes the following emails:
cesarcastillo88#hotmail.com ; laura23#gmail.com ; test#compliance.com
I did it perfectly for those cases with only 1 email in a single record
I used the following formula:
substring(**columnName**, charindex('#', sfe.**columnName**), len(sfe.**columnName**))
However, how am I suppose to do it with 3 emails in a single record?
My desired outcome is the following:
hotmail.com ; gmail.com ; compliance.com

Answer 1

Here is a possible solution based on the assumption that you have some sort of ID column that could help to identify each unique row:
;with smpl as (
select *
from (values
(1, 'cesarcastillo88#hotmail.com ; laura23#gmail.com ; test#compliance.com'),
(2, 'abc#cde.net'),
(3, 'laura23#gmail.com ; test#compliance.com')) x(id, email)
), split(id, A, B) as (
select distinct id, CAST(LEFT(email, CHARINDEX(';',email+';')-1) as varchar(100)),
CAST(STUFF(email, 1, CHARINDEX(';',email+';'), '') as varchar(100))
from smpl
union all
select id, CAST(LEFT(B, CHARINDEX(';',B+';')-1) as varchar(100)),
CAST(STUFF(B, 1, CHARINDEX(';',B+';'), '') as varchar(100))
from split
where B > ''
), clr as (
select ID, substring(LTRIM(RTRIM(A)), charindex('#', LTRIM(RTRIM(A))) + 1, len(LTRIM(RTRIM(A)))) cleanEmail
--into #tempTbl
from split
), ccat as (
SELECT DISTINCT ST2.ID,
SUBSTRING(
(
SELECT ';'+ST1.cleanEmail AS [text()]
FROM clr ST1
WHERE ST1.ID = ST2.ID
ORDER BY ST1.ID
FOR XML PATH ('')
), 2, 1000) Emails
FROM clr ST2
)
select * from ccat
And here is some explanation on how this all works:
First CTE expression splits emails into separate rows using ; as a separator
Second CTE is based on your function to remove the recipient from email address and only leave the domain
The last one concatenates everything back and uses same ; as separator. Feel free to add extra spaces around if that's your preferred output.

Answer 2

You don't say what version of SQL Server, but I'll assume 2016 or newer. They key is the STRING_SPLIT function. To join it to your data, you'll want to use CROSS APPLY.
create table #a (
id int identity(1,1),
email varchar(max)
)
insert #a
values ('cesarcastillo88#hotmail.com ; laura23#gmail.com ; test#compliance.com')
, ('dannyboy#irish.com')
select id
, email
, substring(email, CHARINDEX('#', email) + 1, len(email)) as domain
from #a
select a.id
, substring(ltrim(rtrim(b.value)), CHARINDEX('#', ltrim(rtrim(b.value))) + 1, len(ltrim(rtrim(b.value)))) as domain
from #a a
cross apply string_split(email, ';') b
drop table #a