CODEWITHSUNDEEP
phpwordpresswordpress-theming
Zainul Abideen
Zainul Abideen

Reputation: 1900

Compare meta_value in WP_Query that is stored in the form of serialized array

I have a meta box associated with a custom post type. The meta box allows the user to select multiple options from a dropdown and then saves it in the form of the serialized array into the database. If the user selects only one option the meta_value is stored as an integer but if a user selects multiple options then it is saved in the form of a serialized array.

Below are the functions that display and save my meta box

function av_add_meta_box() {

  $post_types = array( 'advertisements' );

  foreach ( $post_types as $post_type ) {

    add_meta_box(
      'avd_screen_meta_box',         // Unique ID of meta box
      'Set Screen',     // Title of meta box
      'av_display_meta_box', // Callback function
      $post_type                   // Post type
    );

  }

}
add_action( 'add_meta_boxes', 'av_add_meta_box' );

// display meta box
function av_display_meta_box( $post ) {

  $value = get_post_meta( $post->ID, '_av_meta_key', true );

  if ( isset( $values['av-meta-box'] ) ) {
        $value = esc_attr( $values['ued-av-box'][0] );
    }

  wp_nonce_field( basename( __FILE__ ), 'av_meta_box_nonce' );

  //echo "<pre>"; print_r($value) ; echo "</pre>";
  ?>
  <select id="av-meta-box" type="text" name="av-meta-box[]" multiple="multiple">
    <option value="">Select Screen</option>
    <?php $screens =  json_decode(apply_filters("av_load_screens", "all")); 
     foreach ($screens as $screen) { 
        $location_name = json_decode(apply_filters("av_load_locations", $screen->location));
        $selected = "";
        if(gettype($value) == "array"){
          $selected = (in_array($screen->id, $value))?"selected":"";
        } else{
          $selected = ($screen->id == $value)?"selected":"";
        }  ?>
        <option <?php echo $selected; ?> value="<?php echo $screen->id; ?>"><?php echo $screen->screen_name." - ".$location_name[0]->location_name." (".$location_name[0]->pin.") "; ?></option><?php
      } ?>
  </select>

<?php

}

// save meta box
function av_save_meta_box( $post_id ) {

  $is_autosave = wp_is_post_autosave( $post_id );
  $is_revision = wp_is_post_revision( $post_id );

  $is_valid_nonce = false;

  if ( isset( $_POST[ 'av_meta_box_nonce' ] ) ) {

    if ( wp_verify_nonce( $_POST[ 'av_meta_box_nonce' ], basename( __FILE__ ) ) ) {

      $is_valid_nonce = true;

    }

  }

  if ( $is_autosave || $is_revision || !$is_valid_nonce ) return;

  if ( array_key_exists( 'av-meta-box', $_POST ) ) {

    update_post_meta(
      $post_id,                                            // Post ID
      '_av_meta_key',                                // Meta key
      array_map( 'strip_tags', $_POST[ 'av-meta-box' ])// Meta value
    );

  }

}
add_action( 'save_post', 'av_save_meta_box' );

And Below are the arguments what I'm passing to my WP_Query

$args = array(
                'post_type' => 'advertisements',
                'meta_query' => array (
                                    'key' => '_av_meta_key',
                                    'value' => 6,
                                    'compare' => 'IN'
                                )
            );

The above WP_Query returns all post with having meta value 6(integer). But what if the meta_value is stored in a serialized array like a:3:{i:0;s:1:"6";i:1;s:1:"7";i:2;s:1:"8";}

In my case, the post_id:20, meta_key:_av_meta_key and meta_value:a:3:{i:0;s:1:"6";i:1;s:1:"7";i:2;s:1:"8";}

I want my WP_Query to return the post with id 20 either the meta_value is 6 or 7 or 8.

Upvotes: 0

Views: 2128

Answers (2)

Anh Tran
Anh Tran

Reputation: 821

I'd suggest saving the (multiple) values into multiple rows in the database to avoid the problem from the beginning. WordPress supports saving multiple values with the same key for a custom field.

You can rewrite the code that saves value to:

if ( array_key_exists( 'av-meta-box', $_POST ) ) {
    delete_post_meta( $post_id, '_av_meta_key' );

    $values = array_map( 'absint', $_POST[ 'av-meta-box' ] );

    foreach ( $values as $value ) {
          add_post_meta( $post_id, '_av_meta_key', $value, false );
    }
}

This way, you can write your query without worrying about serialize data. And getting values from the database is simple as:

$values = get_post_meta( $post_id, '_av_meta_key', false );

PS: I'd suggest using a custom fields plugin to avoid writing repetitive code. It also helps you to solve this problem as I suggested above quickly.

Upvotes: 1

Tameem Safi
Tameem Safi

Reputation: 728

It is difficult to get the correct result using WP_Query with serialised data. You can try using the LIKE keyword instead of IN.

Alternatively you can use a custom $wpdb query to get what you are looking for.

global $wpdb;

$posts = $wpdb->get_results(
  $wpdb->prepare(
    "
    SELECT *
    FROM $wpdb->postmeta
    LEFT JOIN $wpdb->posts as post
    ON post.id = post_id
    WHERE post.post_type = %s
    AND meta_key = %s
    AND meta_value LIKE %s
    ",
    'advertisements',
    '_av_meta_key',
    ':"6";'
  )
);

// Check if anything was found
if( $posts !== NULL ) {
  foreach($posts as $post_info) {
    // $post_info contains all post info as object
    echo $post_info->post_title;
  }
}

You can change the part where it is :"6"; to the value you are looking for. It would make the search better if you wrap the number in :"{number}";" as this is how it is serialised in your example which would make it more of a exact match

Update: Setting meta key for each screen id

function av_add_meta_box() {

  $post_types = array( 'advertisements' );

  foreach ( $post_types as $post_type ) {

    add_meta_box(
      'avd_screen_meta_box',         // Unique ID of meta box
      'Set Screen',     // Title of meta box
      'av_display_meta_box', // Callback function
      $post_type                   // Post type
    );

  }

}
add_action( 'add_meta_boxes', 'av_add_meta_box' );

// display meta box
function av_display_meta_box( $post ) {

  $value = get_post_meta( $post->ID, '_av_meta_key', true );

  if ( isset( $values['av-meta-box'] ) ) {
        $value = esc_attr( $values['ued-av-box'][0] );
    }

  wp_nonce_field( basename( __FILE__ ), 'av_meta_box_nonce' );

  //echo "<pre>"; print_r($value) ; echo "</pre>";
  ?>
  <select id="av-meta-box" type="text" name="av-meta-box[]" multiple="multiple">
    <option value="">Select Screen</option>
    <?php $screens =  json_decode(apply_filters("av_load_screens", "all")); 
     foreach ($screens as $screen) { 
        $location_name = json_decode(apply_filters("av_load_locations", $screen->location));
        $selected = "";
        if(gettype($value) == "array"){
          $selected = (in_array($screen->id, $value))?"selected":"";
        } else{
          $selected = ($screen->id == $value)?"selected":"";
        }  ?>
        <option <?php echo $selected; ?> value="<?php echo $screen->id; ?>"><?php echo $screen->screen_name." - ".$location_name[0]->location_name." (".$location_name[0]->pin.") "; ?></option><?php
      } ?>
  </select>

<?php

}

// save meta box
function av_save_meta_box( $post_id ) {

  $is_autosave = wp_is_post_autosave( $post_id );
  $is_revision = wp_is_post_revision( $post_id );
  $screens     = json_decode(apply_filters("av_load_screens", "all"));

  $is_valid_nonce = false;

  if ( isset( $_POST[ 'av_meta_box_nonce' ] ) ) {

    if ( wp_verify_nonce( $_POST[ 'av_meta_box_nonce' ], basename( __FILE__ ) ) ) {

      $is_valid_nonce = true;

    }

  }

  if ( $is_autosave || $is_revision || !$is_valid_nonce ) return;

  if ( array_key_exists( 'av-meta-box', $_POST ) ) {

    $selected_screens = array_map( 'absint', $_POST[ 'av-meta-box' ] );

    foreach($screens as $screen) {
      update_post_meta(
        $post_id,
        '_av_meta_key_' . $screen->id,
        in_array( $screen->id, $selected_screens ) ? 'yes' : 'no'
      );
    }

  }

}
add_action( 'save_post', 'av_save_meta_box' );

Then when you want to use WP_Query you can build an array to search for all keys and set the relation to OR.

$meta_query = [
  'relation' => 'OR',
];

$screens    = json_decode(apply_filters("av_load_screens", "all"));

foreach($screens as $screen) {
  $meta_query[] = [
    'key'       => '_av_meta_key_' . $screen->id,
    'value'     => 'yes',
    'compare'   => '='
  ];
}

$args = array(
  'post_type'  => 'advertisements',
  'meta_query' => $meta_query,
);

Upvotes: 1

Related Questions