How to seperate results from a mysql select - php

Question

I apologize for this beginner question but unfortunately it is my level.
I have a fairly simple web page for my work, it is a index.php page that when opened goes out to a DB and retrieves the contents of a certain column. It then places the results in a drop down pick list.
Here is my problem, this column is a list of materials for customers. Some customers have more than 1 different type of material, while others have one.
Therefore my pick list can look like:
Apple /n
Orange; Apple; banana/n
banana;peach /n
orange/n
I am trying to come up with something that when I pull the data from the mysql DB that my php seperates the materials and only provides unique items.
Here is my code for creating picklist:
<p><select size="1" name="material" ID="material" onChange="showfield(value);">
<option value=''><None></option>;
<?php
while ($row = mysql_fetch_array($query))
{
$rowmod = strtr($row['material']," ","_");
echo "<option value='$rowmod'>$row[material]</option>";
}
?>
Here is my mysql select:
$query="select distinct material from TABLE-A order by material";
Update:
I think my Mysql is right, I think I played around with the php strtr and I was able to remove the ; and add lines in, but now I do not know how to make it cycle through and create my
here is the new code:
$row[product]";
}
?>
some output from my $row will have only one product, some will have 2 or more, I wonder if I have to put another while loop after the $rowmod?
I have a feeling I am close, but hoping for some guidance.

Answer 1

First of all, you should make a material table, indexed with an auto_increment id, and use that ID in what you call TABLE-A in a column material_id. Like that you'll have a list of unique material in one table dedicated to it, where you can even add some columns for the details of the material, etc..
Then I am unsure of your needs/use-case, but it looks like you'll need a customer_material table to link a customer with its material(s) so that you know which customer uses which material. It would have an id auto-incremented, as it should always be for any table for better practices, a customer_id and a material_id, with an unique index on the both last columns (customer_id+material_id) to be sure you link one material to one customer only once and not many time each material for the same customer.
Then when you'll need to list the materials for a given customer, just use this query:
select m.id, m.name
from customer_material cm
join material m on cm.material_id = m.id
where cm.customer_id = YOUR_CUSTOMER_ID
If you need to list all materials uniquely, you;ll then need this query:
select m.id, m.name
from material m
order by m.name /* optional, to order by the material name */
And voila. As I am unsure of your use-case the schema of the DB might be a bit different, but I think anyway the main problem in your issue is that the DB is not well architected. Lemme know if I something is unclear here.

Answer 2

You mentioned that different customers have different materials, but that is not reflected in your SQL query because there is no WHERE clause, meaning that you are selecting all unique values from the materials table regardless of any condition. But with that aside, I think that if you change your code slightly you will get some data.
$query="select distinct `material` from `TABLE-A` order by material"
<p><select size="1" name="material" ID="material" onChange="showfield(value);">
<option value=''><None></option>;
<?php
while ($row = mysql_fetch_assoc($query))
{
$rowmod = strtr($row['material']," ","_");
echo "<option value='$rowmod'>$row['material']</option>";
}
?>