Question

I am trying to create a custom sort that involves the count of some records in another table. For example, if one record has no records associated with it in the other table, it should appear higher in the sort than if it had one or more records. Here’s what I have so far:

SELECT People.*, Organizations.Name AS Organization_Name,
   (CASE
        WHEN Sent IS NULL AND COUNT(SELECT * FROM Graphics WHERE People.Organization_ID = Graphics.Organization_ID) = 0 THEN 0
        ELSE 1
    END) AS Status
FROM People
LEFT JOIN Organizations ON Organizations.ID = People.Organization_ID
ORDER BY Status ASC

The subquery within the COUNT is not working. What is the correct way to do something like this?

Update: I moved the case statement into the order by clause and added a join:

SELECT People.*, Organizations.Name AS Organization_Name
FROM People
LEFT JOIN Organizations ON Organizations.ID = People.Organization_ID
LEFT JOIN Graphics ON Graphics.Organization_ID = People.Organization_ID
GROUP BY People.ID
ORDER BY
  CASE
    WHEN Sent IS NULL AND Graphics.ID IS NULL THEN 0
    ELSE 1
  END ASC

So if if the People record does not have any graphics, Graphics.ID will be null. This achieves the immediate need.

Answer 1

If what you tried does not work, it can be done by joining against a subquery, and placing the CASE expression into ORDER BY as well:

SELECT 
  People.*,
  orgcount.num
FROM People JOIN (
  SELECT Organization_ID, COUNT(*) AS num FROM Graphics GROUP BY Organization_ID
) orgcount ON People.Organization_ID = orgcount.num
ORDER BY 
   CASE WHEN Sent IS NULL AND orgcount.num = 0 THEN 0 ELSE 1 END,
   orgcount.num DESC