Question

I have a table called Request.
Other tables are linked to the Request table through a request id.
There is a TwitterTweet table and a FacebookPost table.
So a single request can have 50 TwitterTweets and/or 20 FacebookPosts or any amount of Tweets/Posts
We can add them together for a total count of 70.

I’m trying to create a query that could tell me what is the request with the highest total count.

I know this is wrong:
(I attempted to just order them by the counts within the TwitterTweet, but it would not let me do an OUTER JOIN which I thought
would bring back the Count.count column. It forced me to do a Left Join for it to compile. My Logic was to do a join so
that the results were calculated for each row by the requestid)

SELECT r1.`id` AS requestid, r1 . * 
FROM  `Request` AS r1
LEFT JOIN 

(SELECT COUNT( * ) AS count, rid
FROM 

((SELECT  `TwitterTweet`.`id` AS  `smid` ,  `TwitterTweet`.`requestid` AS rid
FROM  `TwitterTweet` 
WHERE  `TwitterTweet`.`requestid` = requestid
AND  `TwitterTweet`.`active` =1) AS talias

)) AS Count ON ( Count.rid = requestid ) 
ORDER BY Count.count

*When I tried to add in the Facebook side it would not compile any more
(The concept is that the results are added from TwitterTweet with the results from FacebookPost
that are attached to the specific requestid which would give us a count. The entire result
set should be ordered by that count)

SELECT r1.`id` AS requestid, r1 . * 
FROM  `Request` AS r1
LEFT JOIN 

(SELECT COUNT( * ) AS count, rid
FROM 

((SELECT  `TwitterTweet`.`id` AS  `smid` ,  `TwitterTweet`.`requestid` AS rid
FROM  `TwitterTweet` 
WHERE  `TwitterTweet`.`requestid` = requestid
AND  `TwitterTweet`.`active` =1 ) AS talias 

UNION All

(SELECT `FacebookPost`.`id` AS  `smid`, `FacebookPost`.`requestid` AS rid
FROM  `FacebookPost`
WHERE  `FacebookPost`.`requestid` = requestid
AND  `FacebookPost`.`active` = 1) as falias 

)) AS Count ON ( Count.rid = requestid ) 
ORDER BY Count.count

I updated the Query with an attempt to add an alias:

SELECT rid, SUM(count) total_count

FROM 

(
(SELECT COUNT(*) AS count, r.rid
FROM   request r
       JOIN TwitterTweet tt
       ON r.id = tt.requestid
WHERE  tt.active = 1
GROUP BY r.rid) AS twitter

UNION ALL

(SELECT COUNT(*) AS count, r.rid
FROM   request r
       JOIN FacebookPost fp
       ON r.id = fp.requestid
WHERE  fp.active = 1
GROUP BY r.rid ) AS fbook
)

GROUP BY rid

ORDER BY SUM(count) DESC

I made another adjustment to give the middle subquery an alias, but now I only get one row returned with a zero in the rid column and 5686 in the total_count column…the 5686 might be all of the results.

SELECT counts.rid, SUM(count) total_count

FROM 

(
SELECT COUNT(*) AS count, r.requestid AS rid
FROM   request r
       JOIN TwitterTweet tt
       ON r.id = tt.requestid
WHERE  tt.active = 1
GROUP BY r.requestid

UNION ALL

SELECT COUNT(*) AS count, r.requestid AS rid
FROM   request r
       JOIN FacebookPost fp
       ON r.id = fp.requestid
WHERE  fp.active = 1
GROUP BY r.requestid
) AS counts

GROUP BY counts.rid

ORDER BY SUM(count) DESC

Got it!!!
Thanks for your help guys, I had to remove those joins on the request:

SELECT counts.rid, SUM(count) total_count

FROM 

(
SELECT COUNT(*) AS count, tt.requestid AS rid
FROM  TwitterTweet tt
WHERE  tt.active = 1
GROUP BY tt.requestid

UNION ALL

SELECT COUNT(*) AS count, fp.requestid AS rid
FROM   FacebookPost fp
WHERE  fp.active = 1
GROUP BY fp.requestid
) AS counts

GROUP BY counts.rid

ORDER BY SUM(count) DESC

Answer 1

SELECT id, SUM(count) total_count

FROM 

(
SELECT COUNT(*) AS count, r.id
FROM   request r
       JOIN TwitterTweet tt
       ON r.id = tt.requestid
WHERE  tt.active = 1
GROUP BY r.id

UNION ALL

SELECT COUNT(*) AS count, r.id
FROM   request r
       JOIN FacebookPost fp
       ON r.id = fp.requestid
WHERE  fp.active = 1
GROUP BY r.id
) sub

GROUP BY id

ORDER BY SUM(count) DESC
;