Question

This is the query I use:

$idList="32,33,21,11";          
$query = "SELECT post_id, meta_value FROM wp_posts 
          WHERE meta_key = 'grade' AND post_id IN ($idList)";

As a result, the where clause become keys:

$result = array(
              0 => array('post_id'=> 32, 'meta_value'=>5),
              1 => array('post_id'=> 33, 'meta_value'=>2),
              2 => array('post_id'=> 21, 'meta_value'=>8),
           )

I desire to have a result like this:

$result = array(
              0 => array( 32 => 5 ),
              1 => array( 33 => 2 ),
              2 => array( 21 => 8 ),
           )

How to achieve this? Thanks!

Answer 1

Loop through the result set like this:

$_final = array(); // new result set

foreach ($result as $value)
  $_final[] = array($value['post_id'] => $value['meta_value']);

unset($result); // free memory from old result set

UPDATE: If there are too many element and you afraid of memory consumption, you can do it the following way:

$_final = array(); // new result set

foreach ($result as $key => $value) {
  $_final[] = array($value['post_id'] => $value['meta_value']); // composing new data
  unset($result[$key]); // unsetting already parsed value
}

unset($result); // freeing memory from old result set