How to input content for particular topic to database in php?

[yateesh]

I have recent topics displayed on my home page . When i click on any topic , it opens in a new page with full details of that topic . There is an option( a form ) where users can write review for that particular topic .

Question : How do i select number of reviews of a particular topic from table to display next to it on home page ?

This is my 1st table for Topics.

 Topic_Id  -  1 , 2 , 3  
 Title  -  First Topic , Second Topic , Third Topic 
 Category_ID  -   3 , 1 , 1  
 Date  -   yyyy-mm-dd
 

This is my 2nd table for Category.

 Category_ID  -  1 , 2 , 3
 Category_name   -  PHP , MYSQL , PDO
 

This is to input .

try 
   {
   $query = $conn->prepare("INSERT INTO `topics`     (title,category_id) VALUES  (:title,:category_id)");
 
   $query->execute(array(
        'title'       => $_POST['title'],
        'category_id' =>    $_POST['category_id'],
                                    )); 
        }
 
   catch (PDOException $e) 
   {
   error_log($e->getMessage());
   die($e->getMessage());
   }
 

This is to display on home page .

   $sql = "SELECT * FROM review ORDER by pid DESC limit  0,3";
 
   $q    = $conn->query($sql);
 
   $q->setFetchMode(PDO::FETCH_ASSOC);
 
   while($row = $q->fetch()){
      echo $row['title'];
      echo $row['username'];
   }
 
 

This is my 3rd table for inserting reviews .

 Topic_ID  -  
 Rating  -  
 Review  -  
 User_ID  -
 

[Rabbit]

You can run a count(*) query grouping by your topic and use that to output the number of reviews next to each topic.