Question

HI all i have an issue echoing out my data.
I have three tables, one for students, classes and student_classes.
I’ve queried the db to joint the all three so i can see all students, whether they have enrolled in a class or not with their class. the sql is

SELECT students.id, students.student_name, students.student_number,
section_student.ss_id, section_student.section_number,sections.subject 
FROM students 
LEFT JOIN student_classes
ON students.student_number=student_classes.student_number 
LEFT JOIN classes 
ON classes.class_number=student_classes.class_number 
WHERE students.status=1

This produces a list of students with classes if they have them. for those students who have enrolled in more than one course there name shows twice in the list.

When i print_r the data i get

Array
(
[0] => stdClass Object
    (
        [class_number] => 
        [student_name] => john smith
        [student_number] => 432100351
        [id] => 2
        [ss_id] => 
        [subject] => 
        [user_email] => [e-mail]
        [created_at] => 0000-00-00 00:00:00
        [updated_at] => 0000-00-00 00:00:00
    )

[1] => stdClass Object
    (
        [class_number] => 43223
        [student_name] => Paul jones
        [student_number] => 432100312
        [id] => 3
        [ss_id] => 40
        [subject] => Maths
        [user_email] => [e-mail]
        [created_at] => 0000-00-00 00:00:00
        [updated_at] => 2012-11-24 08:33:23
    )

[2] => stdClass Object
    (
        [class_number] => 21331
        [student_name] => Paul jones
        [student_number] => 432100312
        [id] => 3
        [ss_id] => 39
        [subject] => Physics
        [user_email] => [e-mail]
        [created_at] => 0000-00-00 00:00:00
        [updated_at] => 2012-11-24 08:33:23
    )

When i do a for each in a table to show the students and their class I want to loop through the classes that a student has in one line. eg

john ID:432100351 | N/A
Paul ID:432100312 | 43223 = Maths , 21331 = Physics

When i do my loops i get

ID:432100351 john | [e-mail] | N/A
ID:432100312 Paul | [e-mail] | 43223 = Maths , 21331 = Physics
ID:432100312 Paul | [e-mail] | 43223 = Maths , 21331 = Physics

Im not sure if the problem is with my sql or my loop

Here is the code

@foreach ($students as $student)
<tr>
<td> {{ $key++ }}</td>
<td> {{ HTML::link('students/edit/' .$student->id, $student->student_number) }} </td>
<td> {{ HTML::link('students/edit/' .$student->id, $student->student_name) }} </td>
<td> {{ $student->user_email }} </td>
<td>


    @if(!isset($student->ss_id)) 

        {{ HTML::link('add_student_section.php?student_id='.$student->id,'Add to section'); }}

    @else 

        @foreach($students as $section) 

         {{ HTML::link('edit_student_section.php?ss_id=', $section->section_number . " " . $section->subject . " ") ;}}     

        @endforeach

    @endif    

</td>
<td> {{ date("d-M-Y H:i",strtotime($student->created_at )) }} </td>
<td> 
@if($student->updated_at == $student->created_at)

N/A

@else

{{ date("d-M-Y H:i",strtotime($student->updated_at )) }} 
@endif

</td>
<td> {{ HTML::link('students/delete/' .$student->id, 'Delete Student') }} </td>
</tr>
@endforeach

Any help would be appreciated. Thanks

Answer 1

You need to use GROUP BY in conjunction with GROUP_CONCAT

SELECT students.id, students.student_name, students.student_number,GROUP_CONCAT(classes.class_number) as student_classes
FROM students 
LEFT JOIN student_classes
ON students.student_number=student_classes.student_number 
LEFT JOIN classes 
ON classes.class_number=student_classes.class_number 
WHERE students.status=1 GROUP BY students.id