Query WooCommerce Products based on Attribute - wordpress

Question

This one's driving me nuts.. I'm trying to query and output WooCommerce products based on a specific attribute. For example, I set up an Attribute called on, with possible values of yes or no.
I query using the following:
$args = array(
'post_type' => 'product',
'meta_key' => 'pa_on',
'meta_value' => 'yes',
'posts_per_page' => -1
);
query_posts($args);
The meta_key is crucial perhaps; if I call it on I get nothing. If I call it pa_on (because that's how I understand WooCommerce custom attributes to be constructed) I get nothing.
However, if I try a different query and use _featured, which is a standard WooCommerce custom meta thingy, it returns the relevant featured posts. Help, anyone?

Answer 1

I know this is an old one, but just in case someone stumbles upon it like I did today -- Woocommerce (I'm using v2.6.2) appears to store these custom attributes as taxonomies.
I suspect the correct args for the original question would look like this:
$args = array(
'post_type' => 'product',
'tax_query' => array(
array(
'taxonomy' => 'pa_on',
'field' => 'name',
'terms' => 'yes'
)
)
);
Using the appropriate values for my installation, it solved my problem.

Answer 2

For new woocommerce use:
$attribute = 'on';
$value = 'yes';
$args = array(
'post_type' => 'product',
'tax_query' => array(
array(
'taxonomy' => 'pa_' . $attribute,
'terms' => $value,
'field' => 'slug',
'operator' => 'IN'
)
)
);

Answer 3

If product attribute is saved as specific product attribute (i.e. not global), then you can't query it as taxonomy, instead you can use this snippet (copied from http://snippet.fm/snippets/query-woocommerce-products-product-specific-custom-attribute/):
// Set custom attribute name and value to search for
$attribute_name = 'color';
$attribute_value = 'green';
$serialized_value = serialize( 'name' ) . serialize( $attribute_name ) . serialize( 'value' ) . serialize( $attribute_value ); // extended version: $serialized_value = serialize( $attribute_name ) . 'a:6:{' . serialize( 'name' ) . serialize( $attribute_name ) . serialize( 'value' ) . serialize( $attribute_value ) . serialize( 'position' );
$args = array(
'post_type' => 'product',
'post_status' => 'any',
'posts_per_page' => -1,
'orderby' => 'title',
'order' => 'ASC',
'meta_query' => array(
array(
'key' => '_product_attributes',
'value' => $serialized_value,
'compare' => 'LIKE',
),
),
);
$loop = new WP_Query( $args );
while ( $loop->have_posts() ) {
$loop->the_post();
// do stuff here... e.g. get_the_ID()
}
wp_reset_postdata();

Answer 4

Guess what you need is a query with meta_query value set:
$args = array(
'post_type' => 'product',
'meta_query' => array(
array(
'key' => 'pa_on',
'value' => 'yes',
'compare' => '='
)
)
);
$query = new WP_Query( $args );
You can learn more about those here:
http://codex.wordpress.org/Class_Reference/WP_Query#Custom_Field_Parameters