Irritative sql statement help needed

问题:

I have a table that has a column with comma delimited email addresses. Is there a way in a single select statement to parse them out and do a group by on them?

In a table like this:

ID     Emails
1      [e-mail], [e-mail]
2      [e-mail], [e-mail]

Return something like:

Email                Count
email@domain         1
[e-mail]    2
[e-mail]    1 

i know i can do this with cursors and temp tables, but i wasn't sure if there was some neat trick to doing this with a select and nested select statements.

Thanks in advance.

回答1:

You can convert your email list to XML and then query the XML using .nodes and .value.

declare @T table
(
  ID int,
  Emails varchar(100)
)

insert into @T values
(1, '[e-mail], [e-mail]'),
(2, '[e-mail], [e-mail]')

select T.Email, count(*) as [Count]
from (
      select X.N.value('.',  'varchar(30)') as Email
      from @T
        cross apply (select cast('<x>'+replace(Emails, ', ', '</x><x>')+'</x>' as xml)) as T(X)
        cross apply T.X.nodes('/x') as X(N)
     ) as T
group by T.Email

Result:

Email                          Count
------------------------------ -----------
[e-mail]               1
[e-mail]              2
[e-mail]              1

回答2:

Your problem seems very similar to the one posed in this question: Turning a Comma Separated string into individual rows.

A recursive CTE, as was done there, should work.

回答3:

I'll have to sit and digest this one a little bit, because never played with MSSQL xml stuff before, but i changed it to use my actual table name and it works PERFECTLY, omg, thank you so much. Here's what i did (in case someone wants to use this without a temp table like me):

select T.Email, count(*) as [Count] 
from ( 
      select X.N.value('.',  'varchar(30)') as Email 
      from reports_schedule rs
        cross apply (select cast('<x>'+replace(rs.recipient_email, ', ', '</x><x>')+'</x>' as xml)) as T(X) 
        cross apply T.X.nodes('/x') as X(N) 
     ) as T 
group by T.Email 

thanks again!