If remove WHERE from code it works other time it does not

Question

if(isset($_GET['open'])){
    $sub_id = $_GET['open'];
    $sub_query = "SELECT * FROM `forum_sub` WHERE s_id = $sub_id";
    $sub_run  = mysqli_query($connection, $sub_query); 
    $sub_row  = mysqli_fetch_array($sub_run);
    $sub_name = $sub_row['title']; 
    }

/*** 
 * Error starts here: 
 ***/
$topic_query = "SELECT * FROM `forum_topic` WHERE categories = $sub_name";
$topic_run = mysqli_query($connection, $topic_query);

/***  
 * Note also here:
 ***/
 while($topic_row = mysqli_fetch_array($topic_run)){ 
       $p_id = $topic_row['id'];
       $p_title = $topic_row['subject'];
       $p_msg =$topic_row['msg'];
       $p_date = $topic_row['date'];
       $p_username = $topic_row['u_name'];
       $p_view = $topic_row['view'];
      }

When I Remove WHERE then it is okay otherwise it gives error

Please help me

I tried every way but it just not happening. if I remove WHERE tag then it is happening properly

forum_topic structure

1. Do you have a `categories` field in the `forum_topic` table? 2. **Please learn about [SQL injection](http://php.net/manual/en/security.database.sql-injection.php)!** 3. Why use `SELECT *` when you only really need `title` from the first query? 4. You would be much better to use [`JOIN`](http://www.sql-join.com/) — BenM, Feb 05 '17 at 18:10
yeah I have and that categories of forum_topic is equall to $sub_name = $sub_row['title']; of forum_sub — T.mandal, Feb 05 '17 at 18:12
Please post the error you are having. You're missing a } to close the while loop in your code. — Loveen Dyall, Feb 05 '17 at 18:13
Warning: mysqli_fetch_array() expects parameter 1 to be mysqli_result, boolean given no i have closed it properly please look little down — T.mandal, Feb 05 '17 at 18:15
hello sir please look find it in question area .i have uploaded it — T.mandal, Feb 05 '17 at 18:28
why do you have `**` in your code? comment blocks are `/*` ... `*/` — Martin, Feb 05 '17 at 18:33

score -1 · Accepted Answer · answered Feb 05 '17 at 18:18

-1

use this

$sub_query = "SELECT * FROM `forum_sub` WHERE s_id =". $sub_id;

answered Feb 05 '17 at 18:18

Arslan Bilal

625
2
9
17

actually i can fetch data from that table but unable from forum_topics – T.mandal Feb 05 '17 at 18:24
you are doing same mistake in the forum_topics – Arslan Bilal Feb 05 '17 at 18:26
$topic_query = "SELECT * FROM `forum_sub` WHERE categories =". $sub_name; It is also giving same result – T.mandal Feb 05 '17 at 18:29
did you change in the forum_topics as well? – Arslan Bilal Feb 05 '17 at 18:35
yes sir. I have changed in for both the table. forum_sub is perfectly running but forum_topic is not – T.mandal Feb 05 '17 at 18:38

score -1 · Answer 2 · answered Feb 05 '17 at 18:33

-1

Your variables placed inside of the if statement are undefined when outside of the if statement.

Try

if(isset($_GET['open'])){
$sub_id = $_GET['open'];
$sub_query = "SELECT * FROM `forum_sub` WHERE s_id = $sub_id";
$sub_run  = mysqli_query($connection, $sub_query); 
$sub_row  = mysqli_fetch_array($sub_run);
$sub_name = $sub_row['title']; 

   $topic_query = "SELECT * FROM `forum_topic` WHERE categories = $sub_name";
   $topic_run = mysqli_query($connection, $topic_query);

   while($topic_row = mysqli_fetch_array($topic_run)){
   $p_id = $topic_row['id'];
   $p_title = $topic_row['subject'];
   $p_msg =$topic_row['msg'];
   $p_date = $topic_row['date'];
   $p_username = $topic_row['u_name'];
   $p_view = $topic_row['view'];
  }
}

answered Feb 05 '17 at 18:33

Loveen Dyall

824
2
8
20

Sir i have tried this but it is also not happening :( – T.mandal Feb 05 '17 at 18:36
Is it reporting any errors? – Loveen Dyall Feb 05 '17 at 18:38
same error mysqli_fetch_array() expects parameter 1 to be mysqli_result, boolean given – T.mandal Feb 05 '17 at 18:40
Are you sure you're copying the code correctly as I'm trying the same code and there aren't any errors? Double check the curly braces are in the right place. – Loveen Dyall Feb 05 '17 at 18:41
i am sorry to say it sir but i'm having same error – T.mandal Feb 05 '17 at 18:42
Can you update your question with the new code please? thanks. – Loveen Dyall Feb 05 '17 at 18:47
Which code you gave i updated..still not happening.. i m very sad and i will leave this profession . – T.mandal Feb 05 '17 at 19:01
I'm very sorry you're frustrated but as I mentioned, I have replicated the error only when the variables are being called outside of the if statement. When called from inside the if statement, there aren't any errors on my side. – Loveen Dyall Feb 05 '17 at 19:03
Is that error occurs from table structure? – T.mandal Feb 05 '17 at 19:05
No it occurs because your referencing variables which are defined inside the if statement. Place the entire code in the if statement to make it work. – Loveen Dyall Feb 05 '17 at 19:08
Sir as u said i habe done but same result.and before that same kind of coding i have done successfully but this time i cant do this..i am bad and very bad man in this world – T.mandal Feb 05 '17 at 19:09

If remove WHERE from code it works other time it does not

2 Answers2