Populate dropdown from Another MySQL table - php

Question

I want to populate course list inside a dropdown but use the id from the student table to select its value in the edit page.

Database

course
+----+-------------+
| id | course_name |
+----+-------------+
| 1  | English     |
| 2  | Math        |
| 3  | Social      |
| 4  | Arts        |
| 5  | History     |
+----+-------------+

student
+----+--------+-----+--------+
| id | name   | age | course |
+----+--------+-----+--------+
| 1  | John   | 25  | 1      | /* English */
| 2  | Robert | 24  | 3      | /* Social */
| 3  | Nancy  | 21  | 4      | /* Arts */
+----+--------+-----+--------+  

I am populating the course table database inside a dropdown like this in the create new student page.

Create New student

$dropdown_query = "SELECT * FROM course";

// other codes

echo "<select name='course' value='' required/>";
    echo "<option value=''> Select the Course </option>";
    foreach (mysqli_query($con, $dropdown_query) as $row){
        echo "<option value='".$row['id']. "'> $row[course_name] </option>";
    }
echo "</select>";   

// other codes

HTML output

┌────┬────────┬─────┬─────────┬────────┐
│ id │  name  │ age │ course  │  Edit  │
├────┼────────┼─────┼─────────┼────────┤
│  1 │ John   │  25 │ English │ [Edit] │
│  2 │ Robert │  24 │ Social  │ [Edit] │
│  3 │ Nancy  │  21 │ Arts    │ [Edit] │
└────┴────────┴─────┴─────────┴────────┘

Edit Student page

I am stuck here

$id = '';
if( isset( $_GET['id'])) {
    $id = $_GET['id'];
}

$dropdown_query = "SELECT * FROM course";
$result = mysqli_query($con, $dropdown_query);

echo "<select name=course value=''> Course </option>";
    while ($row = mysqli_fetch_array($result)) {
        if($row['id'] == $id){
            echo "<option value='".$row['id']. "' selected> $row[course_name] </option>";
        } // if
        else{
            echo "<option value='" .$row['id']. "' >$row[course_name]</option>";
        } // else
    } // while
echo "</select>";

the code above generates the course inside the dropdown list, but the value is not selected. I want to combine two tables into one inside the dropdown.

Please help me!

Answer 1

This is assuming you have an object $student which is the row from students corresponding to the current user.

$dropdown_query = "SELECT * FROM course";
$courses = mysqli_query($con, $dropdown_query);

echo '<select name="course">';
    while ($course = mysqli_fetch_array($courses)) {
        echo "<option value='{$course['id']}'".($student['course']==$course['id'] ? ' selected="selected"' : '').">{$course['course_name']}</option>";
    } // while
echo '</select>';

Answer 2

Try This

echo "<select name=course value=''> Course </option>";
//ADD EMPTY ELEMENT SO YOU CAN SEE SELECTED ELement
echo "<option value=''> Your Course </option>";
    while ($row = mysqli_fetch_array($result)) {
        if($row['id'] == $id){
            echo "<option value='".$row['id']. "' selected> $row[course_name] </option>";
        } // if
        else{
            echo "<option value='" .$row['id']. "' >$row[course_name]</option>";
        } // else
    } // while
echo "</select>";