Question

Why wont the following work?

SELECT SUM(startUserThreads.newForStartUser)+SUM(endUserThreads.newForEndUser) AS numNew ...

It returns an empty string.

The following is returning 1 for my data set however:

SELECT SUM(startUserThreads.newForStartUser) AS numNew ...

How do I add the two sums correctly?

The whole thing:

SELECT t.*,
       COUNT(startUserThreads.id) + COUNT(endUserThreads.id)                     AS numThreads,
       SUM(startUserThreads.newForStartUser) + SUM(endUserThreads.newForEndUser) AS numNew
FROM   `folder` `t`
       LEFT OUTER JOIN `thread` `startUserThreads`
         ON ( `startUserThreads`.`startUserFolder_id` = `t`.`id` )
       LEFT OUTER JOIN `thread` `endUserThreads`
         ON ( `endUserThreads`.`endUserFolder_id` = `t`.`id` )
WHERE  user_id = :user

FYI, only two users can share a thread in my model. That should explain my column names

Answer 1

SELECT COALESCE(SUM(startUserThreads.newForStartUser),0)+COALESCE(SUM(endUserThreads.newForEndUser),0) AS numNew ...