php - 使用 mysql COUNT 对多列进行计数

Question

我的表格中有这样的信息:

id    name    recommender
 1    daniel  steve
 2    daniel  tony
 3    steve   daniel

和这段代码:

<h2>Follow/Join Recommendation League Table</h2>
<br/>
<?php

$query = "SELECT name_of_follower, COUNT(name) FROM recommendation_competition_entrants GROUP BY name_of_follower ORDER BY COUNT(name) DESC"; 

$result = mysql_query($query) or die(mysql_error());

// Print out result
while($row = mysql_fetch_array($result)){
        echo $row['name_of_follower'] . " has ". $row['COUNT(name)'] . " entries.";
        echo "<br />";
}

?>

这会计算“名称”列中的所有条目，并显示一个迷你联赛表，如下所示:

daniel - 2 entries
steve - 1 entry

我现在需要做的是从名称和推荐者列中计算名称，因此表格如下所示:

daniel - 3 entries
steve - 2 entries
tony - 1 entry

有没有简单的方法可以做到这一点？

感谢您的帮助

Answer 1

select name_of_follower, 
       count(name_of_follower) 
  from ( select name as name_of_follower 
          from abc 
         union all 
        select follower as name_of_follower  
          from abc
       ) t
 group by t.name_of_follower 
 order by count(name_of_follower) desc