How we filter the search base on post-meta tags

Question

I am using my custom filter. So in this search there are many checkboxes (have city name) and user selected some of them the post show the search result base on the checkbox. First i sotre the city/state name by using the add_post_meta

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

So after that when user filter the post. i am using the code

if ( 'POST' == $_SERVER['REQUEST_METHOD'] && !empty( $_POST['action'] ) && $_POST['action'] == 'sortbydestination' ) :
$stateName = $_POST['stateName'];

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

                            ) 
            );

The checkbox html is generated by jquery which is

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

So the name of the input is a array it self, which give me values like this

stateName[cityname1];
stateName[cityname2];
stateName[cityname3];
stateName[cityname4];

and so on. So someone tell me wether i am using right way to get these data or make correct query or not. Thanks

Answer 1

Thats because you got the meta_query wrong. Check documentation in Codex

Your query should be:

$args = array(
            'posts_per_page' => 30,
            'paged' => $paged, 
            'post_type' => 'post', 
            'post_status' => 'publish',
            'meta_query' => array(
                                array(
                                 'key' => 'post_state',
                                 'value' => $stateName,
                                 'compare' => '=' // not necesary by default is "="
                                )
                            ) 
            );

Basically you need to pass inside the meta_query array, another array with the key and value. Also $stateName should be a var.