abbeyvet - 3:38 pm on Jul 19, 2008 (gmt 0)

What I'm trying to do should be simple, but it is giving me a headache. This is it, simplified from the actual scenario to just leave the part I am struggling with, for clarity:

DB with 2 tables, products and categories from which I want to print a list of categories and their IDs, but only if there are products in the categories.

- categories.catID
- products.productCat (which corresponds to categories.catID)
- categories.catName

I have a query something like this:

$sql = "SELECT * from categories, products WHERE products.productCat=categories.catID";

Then I am printing so:

while ($newArray = mysql_fetch_array($result)){
$catname = $newArray['catName'];
print "<option value=http://www.domain.com/products.php?cat=$newArray[catID]>";
print "$catname";
print "</option>";
}

This suppresses empty categories fine, but it means that the category name is repeated in the list for each product in that category.

How do I either select only unique values of catName, or alternatively print only unique values of catName?

I am thinking it is something to do with array_intersect, but cannot figure out exactly how to use that in this scenario.

Actually I've a feeling I stuck in a warped logic and there is a different and better way of doing what I want that I'm not seeing.