How can I return entries within a certain (non-date) range?

Question

I'd like to make an improvement to how I'm displaying related products on a product detail page. Right now, the list of related products will...

• be limited to the same type and category (Playa relationships)
• be ordered by dollar value in descending order (numeric field)

Sometimes the price alone can make an item dissimilar; for example a $1.5M gum production machine isn't relevant on the detail page for a $0.75 pack of gum. What I'd like to do is limit my related entries to anything within ${x} of the current item.

Here's the (simplified) related products template, to which I pass the IDs of related category pages:

<h3>Related Products</h3>
<ul>
{exp:playa:parents entry_id="{embed:category_ids}" orderby="product_price" sort="desc"}
     <li><a href="{page_uri}">{title}</a>, ${product_price}</li>
{/exp:playa:parents}
</ul>

If I wanted to limit by date, I could use EE's start_on parameter. If I wanted to match a specific value, I know I could use the search paramater. In this case, I simply want to add WHERE product_price <= x, with x being a dollar amount I've already calculated in PHP to be reasonably close to the currently-viewed product. Is there a way to accomplish this without going straight for the query module?

Answer 1

Have a look at Low Search -- it can be used as a replacement for the Channel Entries tag, and has a range parameter which might suit your needs.

Answer 2

Since I love answering my own questions, here's the template embed I ended up with thanks to Derek's suggestion of using Low Search:

<?php 

$pad = 10; // dollar amount above the current price at which we'll cap results
$price_limit = intval('{embed:current_product_price}')+$pad; 

?>

{exp:low_search:results child:product_categories="{embed:category_ids}" range:product_price=";<?php echo $price_limit; ?>" orderby="product_price" sort="desc" parse="inward"}
    <li><a href="{page_uri}">{title}</a>, ${product_price}</li>
{/exp:low_search:results}