SQL Server 2005忽略case语句中的else

Question

I have a SQL query that runs to produce a list of bounced email addresses. The issue I'm having is that no matter what I do I don't get back anything when b.SubscriberKey is either 0 or non-existent. This works fine when b.SubscriberKey is greater than 0.

I believe it has something to do with doing a join on a table that may have no matching rows, but I would've believed that would have resulted in either a count of 0 or null. When I changed my query to test this, I still get nothing.

Edit: I'm looking for the string 'No Bounces' to appear the query runs on a day when I know in fact no bounces have occurred. When run currently the results is completely blank.

Select 
    case 
       when count(b.SubscriberKey) is not null 
          then b.SubscriberKey 
          else 'No bounces' 
    end as SubscriberKey
from 
    _bounce b
Join 
    _Job j with (nolock) on j.JobID = b.JobID
where 
    convert(date, b.EventDate) = convert(date, dateadd(dd, -1, getdate())) 
    and j.EmailID = 66653 
group by 
    b.SubscriberKey

Answer 1

from what I understood, you need Subscriberkeys with value 0 or NULLS also to be displayed in your result and you have also stated that it may not have records in that Join table. As you itself stated, in this scenario the best bet is LEFT Join and not INNER JOIN

Select case when b.SubscriberKey is not null then b.SubscriberKey else 'No bounces' end as SubscriberKey
from _Job j with (nolock)
LEFT Join _bounce b
on j.JobID = b.JobID
where convert(date,b.EventDate)=convert(date,dateadd(dd,-1,getdate())) 
and j.EmailID = 66653 
group by b.SubscriberKey