将这些过滤器添加到functions.php 文件

/**
 * Join posts and postmeta tables
 *
 * @link https://developer.wordpress.org/reference/hooks/posts_join/
 */
add_filter( \'posts_join\', function( string $sql, WP_Query $query ) {
    global $wpdb;
    if ( !is_admin() && $query->get( \'search_meta\' ) ) {
        $sql .= \' LEFT JOIN \' . $wpdb->postmeta . \' ON \' . $wpdb->posts . \'.ID = \' . $wpdb->postmeta . \'.post_id \';
    }
    return $sql;
}, 10, 2 );

/**
 * Modify the search query with posts_where
 *
 * @link https://developer.wordpress.org/reference/hooks/posts_where/
 */
add_filter( \'posts_where\', function( string $sql, WP_Query $query ) {
    global $wpdb;

    if ( !is_admin() && $query->get( \'search_meta\' ) ) {

        $field_query = \'\';

        if ( is_string( $query->get( \'search_meta\' ) ) ) {
            $field_name = $query->get( \'search_meta\' );
            $field_query = "AND {$wpdb->postmeta}.meta_key = \'{$field_name}\'";
        }

        $sql = preg_replace( \'/\\(\\s*\' . $wpdb->posts . \'.post_title\\s+LIKE\\s*(\\\'[^\\\']+\\\')\\s*\\)/\', \'(\' . $wpdb->posts . \'.post_title LIKE $1) OR (\' . $wpdb->postmeta . \'.meta_value LIKE $1\' . $field_query . \')\', $sql );
    }

    return $sql;
}, 10, 2 );

/**
 * Prevent duplicates
 *
 * @link https://developer.wordpress.org/reference/hooks/posts_distinct/
 */
add_filter( \'posts_distinct\', function( string $sql, WP_Query $query ) {

    if ( !is_admin() && $query->get( \'search_meta\' ) ) {
        return \'DISTINCT\';
    }

    return $sql;
}, 10, 2 );

然后你只需要添加search_meta 请求中的参数。要搜索所有元值，请使用\'search_meta\' => true...

add_action( \'wp_ajax_data_fetch\', \'data_fetch\' );
add_action( \'wp_ajax_nopriv_data_fetch\', \'data_fetch\' );
function data_fetch() {

    $recipes = new WP_Query( [
        \'post_type\'     => \'project5\',
        \'orderby\'       => \'rand\',
        \'post_status\'   => \'publish\',
        \'s\'             => esc_attr( $_POST[\'keyword\'] ),
        \'search_meta\'   => true
    ] );

}

或搜索特定字段值使用\'search_meta\' => \'MY_FIELD_NAME\'...

add_action( \'wp_ajax_data_fetch\', \'data_fetch\' );
add_action( \'wp_ajax_nopriv_data_fetch\', \'data_fetch\' );
function data_fetch() {

    $recipes = new WP_Query( [
        \'post_type\'     => \'project5\',
        \'orderby\'       => \'rand\',
        \'post_status\'   => \'publish\',
        \'s\'             => esc_attr( $_POST[\'keyword\'] ),
        \'search_meta\'   => \'keyword\' // Name of custom meta_key
    ] );

}

这还没有完全测试过，所以请记住这一点。

<小时>

EDIT

一种“不太过分”的方法是在WP\\u查询中使用元参数(docs here). 例如

add_action( \'wp_ajax_data_fetch\', \'data_fetch\' );
add_action( \'wp_ajax_nopriv_data_fetch\', \'data_fetch\' );
function data_fetch() {

    $input = esc_attr( $_POST[ \'keyword\' ] );

    $recipes = new WP_Query( [
        \'post_type\'     => \'project5\',
        \'orderby\'       => \'rand\',
        \'post_status\'   => \'publish\',
        \'s\'             => $input,

        \'meta_key\'      => \'MY_CUSTOM_FIELD_DATABSE_KEY\',
        \'meta_value\'    => $input,
        \'meta_compare\'  => \'LIKE\'
    ] );

}