Query by product category, product tags and price in Woocommerce

I am trying to make a simple form to query woocommerce products wine based on form input fields as follows:

• Selected category (Vine type, eg. red wine, white wine etc..) - Input type dropdown

• Select Winery Tag 1 dropdown

• Select Wine Sort Tag 2 dropdown

• Select wine region Tag 3 dropdown

• Price Range dropdown

Filtering by category and price works, however tags give mixed results and i cannot figure out why.

This is how my form looks like to give some context:

Here is my code:

$custom_query_args = array(
      'post_type'               => 'product',
      'post_status'             => 'publish',
      'ignore_sticky_posts' => 1,
      'order'               => 'DESC',
      'posts_per_page'      => 3,
      'product_tag'           => array($tag1, $tag2, tag3), 
      'tax_query'           => array(
             array(
               'taxonomy'       => 'product_cat',
               'terms'      => array( esc_attr( $category ) ),
               'field'      => 'slug',
               'operator'       => 'OR'                            
                      )),
                //Price
                'meta_query' => array(
                    array(
                        'key' => '_price',
                        'value' => array($clow, $chigh),
                        'compare' => 'BETWEEN',
                        'type' => 'NUMERIC'
                    )
              )
        );

From the input fields, I have 3 variables for product tags (like $tag1, $tag2, $tag3), 1 variable for product category (like $category) and 2 variables for the price range (like $clow and $chigh) which are the price from to.

Anyone have an idea why this happens?

There are some little mistakes in your code:

• There is a missing $ in tag3,
• OR is not an operator value (and it's not needed),
• Each Product tag need to be in a separated tax_query array to get your filters working.

So try the following modified code instead:

$custom_query_args = array(
    'posts_per_page'      => 3,
    'post_type'           => 'product',
    'post_status'         => 'publish',
    'ignore_sticky_posts' => 1,
    'order'               => 'DESC',
    'tax_query'           => array(
        // Product category filter
        array(
            'taxonomy' => 'product_cat',
            'terms'    => array( esc_attr( $category ) ),
            'field'    => 'slug',
        ),
        // Product tag 1 filter
        array(
            'taxonomy' => 'product_tag',
            'terms'    => array($tag1),
            'field'    => 'slug',
        ),
        // Product tag 2 filter
        array(
            'taxonomy' => 'product_tag',
            'terms'    => array($tag2),
            'field'    => 'slug',
        ),
        // Product tag 3 filter
        array(
            'taxonomy' => 'product_tag',
            'terms'    => array($tag3),
            'field'    => 'slug',
        ),
    ),
    // Price filter
    'meta_query'  => array( array(
        'key'     => '_price',
        'value'   => array($clow, $chigh),
        'compare' => 'BETWEEN',
        'type'    => 'NUMERIC'
    ) ),
);

Tested and works.