Question

I’m trying to write a simple aggregate query, but struggling with something.

I have a table with a status field that is either ‘Complete’ or ‘Incomplete’.
I want the query to return three rows : the number of complete, number of incomplete, and a calculated percentage of completion.

So far I have the first two rows as

     SELECT Status, Count(*) as countNums FROM tblStuff GROUP BY Status

So this would return something like

 Status    Countnums
 __________         
 Complete  100
 Incomplete 100

And what I want is

 Status    Countnums      Percent
 __________         
 Complete  100             50
 Incomplete 100            50

OR

 Status    Countnums      
 __________         
 Complete  100            
 Incomplete 100           
 percentComplete     50

Although, I don’t see how the latter would work at a row level.
This is in MS Access.

Answer 1

You can use your existing GROUP BY query as a subquery and cross join that with another subquery which returns the total count from tblStuff. Use the subquery values to derive [Percent] in the parent query.

This worked (correct result; no syntax error) with Access 2007:

SELECT
    group_counts.Status,
    group_counts.countNums,
    (group_counts.countNums / total_count.total_nums * 100) AS [Percent]
FROM
    (
        SELECT Status, Count(*) AS countNums
        FROM tblStuff GROUP BY Status
    ) AS group_counts,
    (
        SELECT Count(*) AS total_nums
        FROM tblStuff
    ) AS total_count;

Beware that Percent is a reserved word. Using it as an alias without surrounding it in square brackets threw an error.