MySQL查询工作在SQL，但不是PHP

我有一个名为HWC的表，我想通过随机行，我的数据库有大约10k个条目，我之前使用的方法太慢了。

这是我的查询:

SELECT *
FROM HWC AS r1 JOIN
   (SELECT (RAND() *
                 (SELECT MAX(id)
                    FROM HWC)) AS id)
    AS r2 WHERE r1.id >= r2.id
ORDER BY r1.id ASC
LIMIT 1

Error Number: 1064
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '* FROM HWC AS r1 JOIN (SELECT (RAND() * (SELECT MAX(id) FROM HWC)) AS id) A' at line 2
SELECT * FROM (`SELECT` * FROM HWC AS r1 JOIN (SELECT (RAND() * (SELECT MAX(id) FROM HWC)) AS id) AS r2 WHERE r1.id >= r2.id ORDER BY r1.id ASC LIMIT 1)

My Full PHP Code for the model:

function random()
{
$query = "SELECT *
FROM HWC AS r1 JOIN
   (SELECT (RAND() *
                 (SELECT MAX(id)
                    FROM HWC)) AS id)
    AS r2 WHERE r1.id >= r2.id
ORDER BY r1.id ASC
LIMIT 1";
$result = $this->db->get($query);
return $result->result_array();
}