PHP / MYSQL Query by id «duplicate ids»

Я пытаюсь получить результаты из трех таблиц, но он повторяет PART_ID и показывает один и тот же идентификатор снова и снова. Как я могу это исправить?

<?php
    $product_list = "";
    $sql = mysql_query("SELECT * FROM PART, PART_TYPE, RACK");
    $productCount = mysql_num_rows($sql);
    if ($productCount >0){

    while($row= mysql_fetch_array($sql)){
                 $id = $row["PART_ID"];
                 $PART_DESC = $row["PART_DESC"];
                 $SERIAL_NUM = $row["SERIAL_NUM"];
                 $RACK_NUM = $row["RACK_NUM"];
                 $PART_TYPE_ID = $row["PART_TYPE_ID"];
                 $PART_TYPE_DESC = $row["PART_TYPE_DESC"];
                 $product_list .= " <strong>PART_ID:</strong> $id -<strong>$PART_DESC</strong> -<strong>Product Type</strong> $SERIAL_NUM - <em><strong>RACK_NUM</strong> $RACK_NUM  - <em> <strong>PART_TYPE_ID</strong> $PART_TYPE_ID  - <em> <strong>PART_TYPE_DESC </strong> $PART_TYPE_DESC   - <em> &nbsp; &nbsp; &nbsp; <a href='inventory_edit.php?pid=$id'>edit</a> &bull; <a href='inventory_list.php?deleteid=$id'>delete</a><br />";
    }

    }else 
        $product_list = "You have not items in the inventory yet"

?>

РЕЗУЛЬТАТЫ

PART_ID: 1001 -Power Mac G4 Desktop -Product Type XBO31 1WAJ3B - RACK_NUM R1S1 - PART_TYPE_ID 101 - PART_TYPE_DESC MAC -       edit • delete
PART_ID: 1001 -Power Mac G4 Desktop -Product Type XBO31 1WAJ3B - RACK_NUM R1S2 - PART_TYPE_ID 101 - PART_TYPE_DESC MAC -       edit • delete
PART_ID: 1001 -Power Mac G4 Desktop -Product Type XBO31 1WAJ3B - RACK_NUM R1S3 - PART_TYPE_ID 101 - PART_TYPE_DESC MAC -       edit • delete
PART_ID: 1001 -Power Mac G4 Desktop -Product Type XBO31 1WAJ3B - RACK_NUM R1S4 - PART_TYPE_ID 101 - PART_TYPE_DESC MAC -       edit • delete
PART_ID: 1001 -Power Mac G4 Desktop -Product Type XBO31 1WAJ3B - RACK_NUM R1S5 - PART_TYPE_ID 101 - PART_TYPE_DESC MAC -       edit • delete
PART_ID: 1001 -Power Mac G4 Desktop -Product Type XBO31 1WAJ3B - RACK_NUM R1S6 - PART_TYPE_ID 101 - PART_TYPE_DESC MAC -       edit • delete
PART_ID: 1001 -Power Mac G4 Desktop -Product Type XBO31 1WAJ3B - RACK_NUM R2S1 - PART_TYPE_ID 101 - PART_TYPE_DESC MAC -       edit • delete
PART_ID: 1001 -Power Mac G4 Desktop -Product Type XBO31 1WAJ3B - RACK_NUM R2S2 - PART_TYPE_ID 101 - PART_TYPE_DESC MAC -       edit • delete
PART_ID: 1001 -Power Mac G4 Desktop -Product Type XBO31 1WAJ3B - RACK_NUM R2S3 - PART_TYPE_ID 101 - PART_TYPE_DESC MAC -       edit • delete
PART_ID: 1001 -Power Mac G4 Desktop -Product Type XBO31 1WAJ3B - RACK_NUM R2S4 - PART_TYPE_ID 101 - PART_TYPE_DESC MAC -       edit • delete
PART_ID: 1001 -Power Mac G4 Desktop -Product Type XBO31 1WAJ3B - RACK_NUM R2S5 - PART_TYPE_ID 101 - PART_TYPE_DESC MAC -       edit • delete
PART_ID: 1001 -Power Mac G4 Desktop -Product Type XBO31 1WAJ3B - RACK_NUM R2S6 - PART_TYPE_ID 101 - PART_TYPE_DESC MAC -       edit • delete
PART_ID: 1001 -Power Mac G4 Desktop -Product Type XBO31 1WAJ3B - RACK_NUM R3S1 - PART_TYPE_ID 101 - PART_TYPE_DESC MAC -       edit • delete
PART_ID: 1001 -Power Mac G4 Desktop -Product Type XBO31 1WAJ3B - RACK_NUM R3S2 - PART_TYPE_ID 101 - PART_TYPE_DESC MAC -       edit • delete
PART_ID: 1001 -Power Mac G4 Desktop -Product Type XBO31 1WAJ3B - RACK_NUM R3S3 - PART_TYPE_ID 101 - PART_TYPE_DESC MAC -       edit • delete