Custom Query problem access the values

Question

Below is the custom query am running on my wordpress site to get the results from postmeta table. When I var_dump the results then I can see the values correctly but when am trying to access a single field from the array, it doesn't work.

Am I missing something?

    <?php
        $key = "sc_event_year";
        $value = $today_year;
        global $wpdb;       
        $query = new WP_Query( array( 'meta_key' => $key, 'meta_value' => $value ) );
        //var_dump($query);
        foreach($query as $result){
            echo $result->post_id;
        }
    ?>

Answer 1

You've asked for an array and you are trying to use an object.

$key = "sc_event_year";
$value = $today_year;
global $wpdb;
$results = $wpdb->get_results("SELECT * FROM $wpdb->postmeta WHERE meta_key = 'sc_event_year' AND meta_value = $value", ARRAY_A);
foreach ($results as $result){
    echo $post_id = $result['post_id']; // <-- here was the problem
}

Unless $value is a number you could have have trouble with that query and I can't tell if there is user-supplied data but prepare is pretty good habit if you are going to be cooking up your own queries.

$key = "sc_event_year";
$value = $today_year;
global $wpdb;
$results = $wpdb->get_results(
  $wpdb->prepare(
    "SELECT * FROM {$wpdb->postmeta} WHERE meta_key = 'sc_event_year' AND meta_value = %s",
    $value
  ),
  ARRAY_A
);
foreach ($results as $result){
 echo $post_id = $result['post_id'];
}

That said, are you sure there are no Core functions or methods that will server your purpose?