SQL Server Count Function Misbehaving

I have a query where I need to get two counts from two different tables.  

select a.BlogPostDate,c.CommentPostDocumentID,b.BlogPostID,a.DocumentID,
Count(b.BlogPostID) NumberLikes,
Count(c.CommentPostDocumentID) NumberComments
from View_Blogs_Joined a
join customtable_BlogPostLikes b on a.DocumentID = b.BlogPostID
join Blog_Comment c on a.DocumentID = c.CommentPostDocumentID
group by a.DocumentID,a.BlogPostDate,b.BlogPostID,c.CommentPostDocumentID

What I am getting back for my counts is a  cartesian product.  The View has 4 records only.  The product is coming in when I join both the counter tables to the View on the same field.  I don't have any other candidates for a match other than the DocumentID.  Any ideas on how I can get the two counts.  I tried a union, but I am getting all the counts back in one column where I need two columns.

Thanks in advance.
sherbug1015Asked:
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Kent OlsenData Warehouse Architect / DBACommented:
Remember the order of operation.  The joins are done first, then the filter (where clause) and finally column selection and aggregation.

So the cartesian product is correct, it's just not the answer that you're looking for.

I think you want something more like this:

select a.BlogPostDate,c.CommentPostDocumentID,b.BlogPostID,a.DocumentID,
(SELECT Count(BlogPostID) FROM customtable_BlogPostLikes x where x.BlogPostID = a.DocumentID) NumberLikes,
(SELECT Count(CommentPostDocumentID) FROM Blog_Comment y where y.CommentPostDocumentID = a.DocumentID) NumberComments
from View_Blogs_Joined a

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Good Luck,
Kent
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Microsoft SQL Server

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