Convert a WP Query into a simpler SQL query to fetch only COUNT of posts

Question

I have this WP Query running for each row in my admin screen for a certain post type:

        $entry_args = array(
            'meta_key'   => 'wp_comp_entry_competition-id',
            'meta_value' => $post_ID,
            'post_type'  => 'wp_comp_entries'
        );
        $entry_query = new WP_Query( $entry_args );

This WP Query fetches all entries for a competition identified by the $post_ID. There is a lot of data since a single competition will have thousands entries.

In consequence, this query repeated multiple times (for each row in an admin screen) is rather slow. Moreover, I do not need all this data. I only want to know the number of entries for each competition identified by $post_ID.

I assume that the way to fetch only the COUNT of entries would be changing this WP Query into a simpler, direct SQL query on WordPress database.

How can I fetch only the number of entries for each competition and not all post data associated with each entry?

Further explanation:

I've now tried fetching only the count of posts with these two approaches:

1) Passing 'fields' => 'ids' to query arguments

        $entry_args = array(
            'meta_key'   => 'wp_comp_entry_competition-id',
            'meta_value' => $post_ID,
            'post_type'  => 'wp_comp_entries',
            'fields'     => 'ids'
        );
        $entry_query = new WP_Query( $entry_args );

and then using $entry_qyery->found->posts to get the number, and

2) Using query_posts like this:

        $entry_args = array(
            'meta_key'   => 'wp_comp_entry_competition-id',
            'meta_value' => $post_ID,
            'post_type'  => 'wp_comp_entries',
            'fields'     => 'ids',
            'posts_per_page' => -1
        );
        $entry_query = query_posts( $entry_args );

and then using count($entry_query) to count all fetched ids (as query_posts returned an array).

My first experience is that query_posts was much slower than WP Query in this case.

Answer 1

You can also try below code to retrieve count of rows.

$myquery = $wpdb->get_results( "SELECT * FROM  tablename WHERE ID='some-value'" );
echo  $wpdb->num_rows;

Let me know if you have any problem.

cheers