selecting sql variable returning an empty array - php

Question

I'm attempting to SET 3 variables in MySQL and get the sum of two of them.
The fist two variables, #cFollow and #cComment, should return an integer value each (the count of how many rows are returned); the third one is the sum of those two integers.
This is my SQL:
SET #cFollow = (SELECT COUNT(*) FROM followers WHERE unix > :unix AND following = :user);
SET #cComment = (SELECT COUNT(*) FROM comments WHERE comment_unix > :unix AND comment_track IN (SELECT upload_id FROM uploads WHERE upload_artist = :user));
SET #total = #cFollow + #cComment;
SELECT #total;
When I tested this on PHPMyAdmin, it returned the correct values and worked perfectly fine. However, when I tested it within PHP, it returned an empty array.
This is my PHP:
$holdPoint = (int)Input::get("hold_point");
$_SQL = "
SET #cFollow = (SELECT COUNT(*) FROM followers WHERE unix > :unix AND following = :user);
SET #cComment = (SELECT COUNT(*) FROM comments WHERE comment_unix > :unix AND comment_track IN (SELECT upload_id FROM uploads WHERE upload_artist = :user));
SET #total = #cFollow + #cComment;
SELECT #total;";
$_PARAMS = [":unix" => $holdPoint, ":user" => $user_id];
$check = DB::getInstance()->queryPro($_SQL, $_PARAMS);
var_dump($check);
This is the result of that var_dump:
array(0){} // not very impressive...
// should be something like int(1) instead
I've been searching around all night learning how to return a variable in PHP from a MySQL query, and this is as far as I've gotten.
All help is appreciated,
Cheers.

Answer 1

This answer is not really meant as a answer but more as a comment.
Also note that your queries
SET #cFollow = (SELECT COUNT(*) FROM followers WHERE unix > :unix AND following = :user);
SET #cComment = (SELECT COUNT(*) FROM comments WHERE comment_unix > :unix AND comment_track IN (SELECT upload_id FROM uploads WHERE upload_artist = :user));
SET #total = #cFollow + #cComment;
SELECT #total;
Can be most likely be rewritten as one query
SELECT
SUM(alias.c) AS total
FROM (
SELECT COUNT(*) AS c FROM followers WHERE unix > :unix AND following = :user
UNION ALL
SELECT COUNT(*) AS c FROM comments WHERE comment_unix > :unix AND comment_track IN (SELECT upload_id FROM uploads WHERE upload_artist = :user)
) AS alias