php - 获取 GROUP BY 中某列的平均值

Question

我通过对引荐来源进行分组来获取数据，并且在每个引荐来源中，我尝试获取每个引荐来源的平均点击次数。例如:

referer a site
--------------
avg clicks: 12


referer b site
--------------
avg clicks: 4

我用这个代码

SELECT *, COUNT(*)
FROM track
GROUP BY referer
ORDER BY id desc
LIMIT 15    

while ($yazdir=mysql_fetch_array($sqlsorgu))
{
    $count = $yazdir['COUNT(*)'];
    $clicks[] = $yazdir[clicks];
    $score_sum = array_sum($clicks);
    $mean_average = $score_sum / $count;
}

但是，它总是计算出错误的数字，也许它也存储了以前的数字。获得每个推荐人的平均点击次数的正确方法是什么？

Answer 1

为什么不

    SELECT *, COUNT(*),AVG(clicks)  
   FROM track GROUP BY referer ORDER BY id desc limit 15