获取GROUP BY中列的平均值

Question

我通过对引用者进行分组来获取数据，并且在每个引用者中，我尝试获取每个引用者的平均点击次数。例如：

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


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

我使用此代码

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; 
} 

然而，它始终计算错误的号码，也许它存储以前的也。什么是正确的方式来获得平均点击每个引用？

Answer 1

为什么不

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