How to get the db table row that has the biggest value in the meta value?

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E.g. I have a meta field called car_number:

So, normally I would try something like this to get this value:

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$car_value = get_post_meta($post->ID, 'car_number');

But the porblem is that I need to get the row only where the car_number is highest e.g. 45. so I need somehow to get the highest value and do something like this: 

$post_ID = .. // here I need to get the ID of the post that has the biggest value in the fild car_value

$car_value = get_post_meta($post_ID, 'car_number');

how can I get the post_ID of the post that has the highest value (number) in car_value meta field?

Post Views: 3

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2 comments

  1. The WP_Query has a feature called meta_query. Using it allows you to either query by value or numeric value:

    $car = new WP_Query( array(
    'post_type'      => array( 'cars' ),
    'meta_key'       => 'car_number',
    'orderby'        => 'meta_value_num',
    'posts_per_page' => 1,
    'order'          => 'DESC',
    'cache_results'  => true,
) );
$carNr = get_post_meta( $car->ID, 'car_number', true );
// Inspect result
var_dump( $carNr );

    Now, that we got the right post type, the appropriate meta key and defined that we want to order by its value, we only need to limit the result to a single post and have a descending order. As we now got the post, we can easily grab the meta value.

    Another option would be to do a plain query:

    global $wpdb;

$wpdb->get_var( 
    "SELECT {$wpdb->postmeta}.meta_value
     FROM {$wpdb->postmeta}
     WHERE 1=1
         AND {$wpdb->postmeta}.meta_key = 'car_number'
     ORDER BY ABS( {$wpdb->postmeta}.meta_value ) DESC
     LIMIT 0,1"
);

    Depending on how you saved your values – often plugins save numbers/digits/integers as strings – you may need to convert your value during the query. In that case replace the order by part with

    CAST( {$wpdb->postmeta}.meta_value as SIGNED INTEGER )

    Note: If you don’t have negative integers, you can go with UNSIGNED

    or 

    CONVERT( {$wpdb->postmeta}.meta_value, SIGNED INTEGER )

  2. Try this method

    function end_meta_value( $end = "max", $meta )
{
    global $wpdb;
    $query = $wpdb->prepare( 
        "SELECT %s( cast( meta_value as UNSIGNED ) ) FROM {$wpdb->postmeta} WHERE meta_key='%s'",
        $end,
        $meta
    );
    return $wpdb->get_var( $query );
}

    from here. For me it worked fine.

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