How we make the filter for fornt end user

Question

I develope a filter for posts so that when any user come to my site they can filter the posts on the base of cities/state. So when i store the posts i just store the cities name as a post-meta tag in the site. The code i am using for adding the post-meta tag is

add_post_meta($post_id, 'post_state' , $state, true);

The html which generating the names of the cities in the form of checkbox is here

for(x in state_arr){
    jQuery('#state_div').append('<label><input type="checkbox" name="stateName['+ state_arr[x] +']" id="" value="'+ state_arr[x] +'" >' + state_arr[x] + '</label');
}

So i pass the name as array.

And the code i am using for filter is here

<?php
if ( 'POST' == $_SERVER['REQUEST_METHOD'] && !empty( $_POST['action'] ) && $_POST['action'] == 'sortbydestination' ) :
$stateName = $_POST['stateName'];
foreach($stateName as $key => $stN) 
{
   $citynames = $stN . ","; 
}
unset($_POST);
endif;

?>

And the argument which i pass to the query is look like this

$args = array(
            'posts_per_page' => 30,
            'paged' => $paged, 
            'post_type' => 'post', 
            'post_status' => 'publish',
            'meta_query' => array(
                            'key' => 'post_state',
                            'value' => array($citynames )

                            ) 
            );

I want to know one thing. Here i in query the value need one value but i have to pass multiple valuse to compare and find the result so how can i do that.

Answer 1

I think the issue is on the meta_query you need to add an other argument like

'compare' => '='

you can also use relation.

I suggest you try the query first.

Answer 2

Meta query expects nested arrays, even if you only have one query. You will have to pass nested array to meta_query as following :

$args = array(
        'posts_per_page' => 30,
        'paged' => $paged, 
        'post_type' => 'post', 
        'post_status' => 'publish',
        'meta_query' => array(  array(
                        'key' => 'post_state',
                        'value' => array($citynames )
                              )
                        ) 
        );

For more information see this page.