How to Change the Relation to 'AND' for the 'in_stock' Condition in WordPress Query

To change the relation to 'AND' for the 'in_stock' condition, you can modify the code as follows:

$idarray=array();
$data = array(
    'post_type' => 'qqproduct',
    'post_status' => 'publish',
    'orderby' => 'DATE',
    'order'   => 'DESC',
    'posts_per_page' => $per_page,
    'paged' => $paged,
);

$meta_query = array(); // Initialize the meta_query array outside the loop

foreach ( $results as $key => $value ) {

    if($key == 'qcat') {
        if($value){
            if($value != 'all' ){
                $cat_query=array('relation' => 'OR',);
                $catos = (explode(',', $value));
                foreach ( $catos as $cato) {
                    $cat_query[] = [
                        'taxonomy' => 'qqcpat',
                        'field' => 'term_id',
                        'terms' => $cato,
                    ];
                    $keys[] = $cato;
                }
                $data['tax_query']=array(array($cat_query),);
            }
        }
    } elseif($key == 'offset') {
    } elseif($key == 'in_stock') {
        $meta_query[] = array(
            'key' => 'qqp_qty',
            'value' => array('0'),
            'compare' => '>'
        );
        $keys[] = 'in_stock';
    } elseif ($key == 'sortby') {
        if ($value == 'newest') {
            $data['orderby'] = 'DATE';
        } elseif ($value == 'discount') {
            $meta_query[] = array(
                'key' => 'qqpd_price',
                'value' => '',
                'compare' => 'NOT IN'
            );
        } elseif ($value == 'review') {
            $meta_query[] = array(
                'key' => 'qq_product_rate',
                'value' => '',
                'compare' => 'NOT IN'
            );
            $data['orderby'] = 'meta_value_num';
        } elseif ($value == 'topsale') {
            $meta_query[] = array(
                'key' => 'qq_total_views',
                'value' => '',
                'compare' => 'NOT IN'
            );
            $data['orderby'] = 'meta_value_num';
        }
        $keys[] = $value;
    } else {
        if ($value) {
            $stros = explode(',', $value);
            $trainer_query = array('relation' => 'OR');
            foreach ($stros as $stro) {
                $trainer_query[] = [
                    'key' => 'qq_att_' . $key,
                    'value' => $stro,
                    'compare' => 'LIKE',
                ];
                $keys[] = $stro;
            }
            $meta_query[] = $trainer_query;
        }
    }
}

if (!empty($meta_query)) {
    $meta_query['relation'] = 'OR'; // Add the relation when meta_query is not empty
    $data['meta_query'] = $meta_query;
}

// Change the relation to 'AND' for the 'in_stock' condition
if (in_array('in_stock', $keys)) {
    $in_stock_query = array(
        'relation' => 'AND',
        $meta_query,
    );
    $data['meta_query'] = $in_stock_query;
}

This code checks if the 'in_stock' condition is included in the query, and if so, creates a new meta_query array with the 'AND' relation and includes the existing meta_query array inside it.