Question

I have a data set which looks similar to:

---------------------------------------------------------------------
id | category | sub_category | category_href | sub_category_href    |
01 | cat_1    | sub_cat 1    | cat/cat1.php  | cat/cat1/sub_cat1.php|
02 | cat_1    | sub_cat 2    | cat/cat1.php  | cat/cat1/sub_cat2.php|
03 | cat_2    | sub_cat 1    | cat/cat2.php  | cat/cat2/sub_cat1.php|
04 | cat_2    | sub_cat 2    | cat/cat2.php  | cat/cat2/sub_cat2.php|
---------------------------------------------------------------------

What I want to do with the data is have a layout like this:

<div>
  <h2 class="title">Cat1</h2>
  <p>
   <ul class="links">
      <li><a href="cat/sub_cat_1.php" target="_top">sub_cat_1</a></li>
      <li><a href="cat/sub_cat_2.php" target="_top">sub_cat_2</a></li>
  </p>
</div>
<div>
  <h2 class="title">Cat2</h2>
  <p>
    <ul class="links">
        <li><a href="cat/sub_cat_1.php" target="_top">sub_cat_1</a></li>
        <li><a href="cat/sub_cat_2.php" target="_top">sub_cat_2</a></li>
    </p>
</div>

So my question is how would I do this with php so that I can change the categories and sub categories from my db. The following is what I have below but I need a second loop for the sub categories or it will only have one sub category per category. Could someone point me in the right direction for the sub_cat loop. Thank you

EDIT:

So my question is now that I have distinct categories how I can echo the appropriate sub categories?

Thanks

<?php
include('connect.php');
$result = mysql_query("SELECT DISTINCT category FROM categories")
    or die(mysql_error());
while ($row = mysql_fetch_array($result)) {
    echo "<div>";
    echo "<h2 class='title'>" . $row['category'] . "</h2>";
    echo "<p>";
    echo "<ul class='links'>";
    $result1 = mysql_query("SELECT * FROM categories ")
        or die (mysql_error());
    while ($row = mysql_fetch_array($result1)) {
        echo "<li><a href='" . $row['sub_category_href'] . " target='_top'>" . $row['sub_category'] . "</a></li>";
    }
    echo "</ul>";
    echo "</p>";
    echo "</div>";
}
?>

Answer 1

That code could be looked like this:

<?php
include('connect.php');
$result = mysql_query("SELECT DISTINCT category FROM categories")
    or die(mysql_error());
while ($row = mysql_fetch_array($result)) {
    echo "<div>";
    echo "<h2 class='title'>" . $row['category'] . "</h2>";
    echo "<p>";
    echo "<ul class='links'>";
    $result1 = mysql_query("SELECT * FROM categories WHERE category = {$row['category']}")
            or die (mysql_error());
    while ($row1 = mysql_fetch_array($result1)) {
        echo "<li><a href='" . $row1['sub_category_href'] . " target='_top'>" . $row1['sub_category'] . "</a></li>";
    }
    echo "</ul>";
    echo "</p>";
    echo "</div>";
}
?>

But I suggest you to optimize in this manner:

<?php
include('connect.php');
$result = mysql_query("SELECT * FROM categories")
    or die(mysql_error());
$cats = array();
while ($row = mysql_fetch_array($result)) {
    $category = $row['category'];
    $sub_category = $row['sub_category'];
    $sub_category_href = $row['sub_category_href'];
    $cat_hrefs[$category][$sub_category] = $sub_category_href;
}
foreach ($cat_hrefs as $category => $sub_category_hrefs) {
    echo "<div>";
    echo "<h2 class='title'>" . $category . "</h2>";
    echo "<p>";
    echo "<ul class='links'>";
    foreach ($sub_category_hrefs as $sub_category => $sub_category_href) {
        echo "<li><a href='" . $sub_category_href . " target='_top'>" . $sub_category . "</a></li>";
    }
    echo "</ul>";
    echo "</p>";
    echo "</div>";
}
?>

You do not need to make three queries, because you can do it in one query, which is more optimal.