Adding an array from a query string to a WP meta_query

Question

I am collecting values from a query string as an array. Then collecting those values and placing them into the value of the 'meta_query'.

I am having trouble where nothing gets outputted from the WP_Query. I feel like there is something wrong with the second array in the 'meta_query'.

I have tried to change the compare to 'LIKE', and that shows all the content instead of what is in the query.

Query string:

?variable[]=value1&variable[]=value2

PHP code:

<?php
$variable_selected = $_GET['variable'];

$filter = array(
    'post_type' => 'my_custom_post_type',
    'meta_query' => array(
        'relation' => 'OR',
         array(
            'key' => 'my_post_field',
            'value' => $variable_selected,
            'compare' => 'IN'
            )
        )

    );

    $posts = new WP_Query( $filter  );

Any help on this will be great.

Answer 1

I would first run a var_dump on $variable_selected to make sure you are getting the array that you need. Also, since you are just using one meta key/value field, you might not need the OR in your query, so you could do something like below. Hope that helps.

<?php
$variable_selected = $_GET['variable'];

// Use the var_dump to test to see if array is being pulled in properly.
var_dump ( $variable_selected );    

$filter = array(
'post_type' => 'my_custom_post_type',
'meta_query' => array(
     array(
        'key' => 'my_post_field',
        'value' => $variable_selected,
        'compare' => 'IN'
        )
    )

);

$posts = new WP_Query( $filter  );

Answer 2

This makes the meta_query dynamic depending on how many values are in the query string.

$meta_query = array();
if ( ! empty( $_GET["variable"] ) ) {
    if ( is_array( $_GET["variable"] ) ) {
        $meta_query['relation'] = 'OR';
        foreach ( $_GET["variable"] as $value ) {
            $meta_query[] = array(
                'key' => 'my_post_field',
                'value' => sanitize_text_field( (string) $value ),
                'compare' => 'LIKE'
            );
        }
    } else {
       $meta_query = array(
            'key' => 'my_post_field',
            'value' => sanitize_text_field( (string) $_GET["variable"] ),
            'compare' => '='
       );
    }
 }
 $filter = array(
    'post_type' => 'my_custom_post_type',
    'meta_query' => array(
       'relation' => 'OR',
       $meta_query
 )
 );
 $posts = new WP_Query( $filter );