Question

我必须将sql table1表示为question而table2表示注释

我希望帖子的评论数量最多

如何在两个表之间进行此操作？

像这样的表格问题

id         title   
-----      -------    
1          title1      
2          title2 
3          title3 
4          title4

像这样的表评论

id         content     questid
-----      -------     -------- 
1          test         1
2          test         3
2          test         3
2          test         3

我的代码

$gquest  = $DB_con->prepare("SELECT * FROM `question` ORDER BY id DESC");
$gquest->execute(); 
foreach ($gquest->fetchAll() as $rowL)    
{
$cat  = $DB_con->prepare("SELECT * FROM `comment` WHERE `questid`=".$rowL['id']."");
$cat->execute();
$cominf = $cat->fetch(PDO::FETCH_ASSOC);     
$countquest = $cat->rowCount();  


$gqt  = $DB_con->prepare("SELECT * FROM `question` ORDER BY ".$cominf['id']." DESC");
$gqt->execute();   
$cfr = $gqt->fetch(PDO::FETCH_ASSOC);    


 }

Answer 1

您可以通过加入问题ID上的两个表，然后COUNT()每个问题的评论出现次数，从单个查询中获取您要查找的内容。以下是它的外观示例：

$gquest  = $DB_con->prepare("
     SELECT q.*, COUNT(c.questid) AS num_comments
     FROM question q
     JOIN comment c
       ON q.id = c.questid
     GROUP BY q.id
     ORDER BY num_comments DESC
     LIMIT 1;
");

这是SQL fiddle

获取两个表之间的数据

1 个答案: