Inner while loop not working

Question

This is a code pinch from a webpage of my project. Here I want to display user selected categories and then want to display its subjects that belong to the categories. There, users could have more than one category, and it is no problem. I can print all those categories in my first while loop. The problem is when I'm trying to print subjects, they only show one row as a result, but there are more subjects in each category. Can anybody tell me what is happening?

This is my code.
Note: Both queries are working properly. I tried those using a mysql client program.

<?php

require_once ('../../includes/config.inc.php');
require_once( MYSQL1 );

$q = "SELECT institute_category.category_id, category_name
      FROM institute_category
      INNER JOIN category ON institute_category.category_id = category.category_id
      WHERE institute_category.institute_id = $instituteId";    

$r = mysqli_query( $dbc, $q);

while ( $row = mysqli_fetch_array ( $r, MYSQLI_ASSOC) )   {

    $categoryId = $row['category_id']; 
    $category = $row['category_name']; 

    echo '<fieldset class="alt">
              <legend><span>Category : <em style="color: red;">' . $category .
              '</em></span></legend>';

    $qy = "SELECT category_subject.category_id, category_subject.subject_id, subjects
           FROM category_subject
           INNER JOIN category ON category_subject.category_id = category.category_id
           INNER JOIN subject ON category_subject.subject_id = subject.subject_id
           WHERE category_subject.category_id = $categoryId";   

    $result = mysqli_query( $dbc, $qy);

    $c = $i = 0;

    echo '<table class="form_table" ><tr>'; 

    while($row = mysqli_fetch_array( $result, MYSQLI_ASSOC  )){
        // if remainder is zero after 2 iterations (for 2 columns) and when $c > 0, end row and start a new row:
        if( ($c % 2) == 0 && $c != 0){
            echo "</tr><tr>";
        }

        echo '<td width="50%"><input type="checkbox" name="subject[]"  value="' . 
              $row['category_id'] . ":" . $category . ":"  . $row['subject_id'] . 
              ":". $row['subjects'] . '" />&nbsp;&nbsp;' . $row['subjects'] . 
              '</td>' . "\n";

        $c++; 

    } // while..

    // in case you need to fill a last empty cell:
    if ( ( $i % 2 ) != 0 ){
        // str_repeat() will be handy when you want more than 2 columns
        echo str_repeat( "<td>&nbsp;</td>", ( 2 - ( $i % 2 ) ) );
    }
    echo "</tr></table>";   
} 
echo '</fieldset>'; 
?>

Only looking at your code for a second I can see that you're using the $rowvariable both for the outer loop and for the inner loop. Try renaming the outer loop's $row variable to $outerRow and the inner loop's $row variable to $innerRow. This may be the first problem. — Thorsten Dittmar
– Thorsten Dittmar, Commented May 21, 2012 at 6:43
chech this query for while list $qy = "SELECT cs.* FROM category_subject cs INNER JOIN category c ON cs.category_id = c.category_id INNER JOIN subject s ON cs.subject_id = s.subject_id WHERE cs.category_id = $categoryId"; — Sam Arul Raj T
– Sam Arul Raj T, Commented May 21, 2012 at 6:47
@SoboLAN: I thought I should post it as a comment as I didn't try anything ;-) — Thorsten Dittmar
– Thorsten Dittmar, Commented May 21, 2012 at 6:47
@SamArulRaj: Why? The OP already said that both SQL queries are working fine when executed directly. — Thorsten Dittmar
– Thorsten Dittmar, Commented May 21, 2012 at 6:48

Thorsten Dittmar · Accepted Answer · 2012-05-21 06:47:06Z

1

Turning my comment into an answer:

Only looking at your code for a second I can see that you're using the $row variable both for the outer loop and for the inner loop. Try renaming the outer loop's $row variable to $outerRow and the inner loop's $row variable to $innerRow. This may be the first problem. This may apply to other variables, too, like for example the $result variable.

answered May 21, 2012 at 6:47

Thorsten Dittmar

56.9k10 gold badges95 silver badges145 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Thorsten Dittmar Over a year ago

Could you please change your question so that it reflects the new source code?

Rohit Choudhary · Accepted Answer · 2012-05-21 06:46:04Z

0

user different variable name for inner loop $result and $row like $inresult and $inrow

answered May 21, 2012 at 6:46

Rohit Choudhary

2,2571 gold badge24 silver badges35 bronze badges

Comments

Punit · Accepted Answer · 2012-05-21 06:50:26Z

0

Because you have used a same variable $row in both of the loops, $row[] in inner loop could be taking reference of outer one and in that result set the variable you are looking for not present so that not printing anything from inner loop, please change the variable of inner or outer loop.

answered May 21, 2012 at 6:50

Punit

1,1201 gold badge8 silver badges15 bronze badges

1 Comment

Punit Over a year ago

just for debugging :first try to find how many records returned by the inner query (echo no. of records for every iteration) based on the outer one if every thing is working fine than go for the html structure.

Collectives™ on Stack Overflow

Inner while loop not working

3 Answers 3

1 Comment

Comments

1 Comment

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

1 Comment

Linked

Related