@tmcmullen you can also do Sub-Select SubQuery.
Then you wouldnt need to do GROUP BY on your Top-Query.
In a Nutshell:
- Make a Sub-Query but DO NOT Use it on the Designer
- On your TopLevel Query add the Sub-Query to a Calculated Field
- On the Sub-Query under SubQuery Criteria you can add WHERE Clause.
Example:
SubQuery1:
SubQuery2:
Result:
Basically in a simpler view it does
SELECT (SELECT count(*) FROM table WHERe...) as YourCalculatedColumn
It is proven that JOINs are usually faster and sometimes SQL will even convert your SUB-SELECT when it can, but if you get into a more complex scenario where you are getting tangled in Sub-Queries, GROUPS, etc… sometimes Sub-Selects work easier. FYI 
thought Id share something.
The best time they work is when you need to get let’s say The Last Approved Revision nothing easier than a SubSelect and then Order By ApprovedDate DESC, but when not using Aggregate like count(*) then you must make sure you set your SubQuery2 to return only 1 row, 1 column.
