Make a slider/select fetching data in php - php

Question

I've got two tables: Subjects and Careers :
"Subjects" includes (id, careers_id (is the foreign key to the column "id" of the table Careers) subject, description, hours)
"Careers" includes (id,name,description)
I put a button which allows me to add a new subject. So when I click on it another page open. I need to add a slider/select which shows me the careers available in the table career. Take a look,I need something like this :
Here is my code to add a new subject (it works,but i dont know how to make the slider/select which fetch data from the table careers :/)
<?php include('connect.php');
$error="";
if(isset($_POST['btnsave']))
{
$carreras_id=$_POST['txtcarreras_id'];
$subject=$_POST['txtsubject'];
$descripcion=$_POST['txtdescripcion'];
$carga_horaria=$_POST['txtcarga_horaria'];
if($_POST['txtid']=="0")
{
$a_sql=mysql_query("INSERT INTO subjects VALUES('','$carreras_id','$subject','$descripcion','$carga_horaria')");
if($a_sql)
{
header("location:index.php");
}
}else{
echo "Actualizar";
}
}
?>
<h2 align="center">ADD NEW SUBJECT</h2>
<form method="Post">
<table align="center">
<tr>
<td>Career:</td>
<td>
<input type='text' name='txtcarreras_id' />
<input type="hidden" name="txtid" value="0" />
</td>
</tr>
<tr>
<td>Subject:</td>
<td>
<input type='text' name='txtsubject' />
</td>
</tr>
<tr>
<td>Description:</td>
<td>
<input type='text' name='txtdescripcion' />
</td>
</tr>
<tr>
<td>Hours:</td>
<td>
<input type='text' name='txtcarga_horaria' />
</td>
</tr>
<tr>
<td></td>
<td>
<input type='submit' value=save name='btnsave' />
</td>
</tr>
</table>
</form>
I don't know what to do?
Hope you can help me!
Thanks!

Answer 1

To build your <option>s you would do something like this ->
$sql = mysql_query("SELECT * FROM Careers");
$options = "";
while($result = mysql_fetch_array($sql)){
$options .= "<option value='".$result['id']."'>".$result['name']."</option>";
}
(Note - you should update from mysql_ to MySQLi or PDO - MySQL: choosing an API )
Then you would change your <input> to a <select> with your $options ->
<tr>
<td>Career:</td>
<td><select name='txtcarreras_id'><?php echo $options; ?></select><input type="hidden" name="txtid" value="0" /></td>
</tr>