Ajax 中 Mysql 请求中的 Wordpress 错误 500

如何解决Ajax 中 Mysql 请求中的 Wordpress 错误 500

您好，我正在 wordpress 中实现一个工具，用户可以在其中选择源语言和目标语言来翻译文件。源语言在页面加载时插入到 options 标签中，当用户选择源语言时，系统需要在数据库中查询以获取所选语言可用的目标语言和需要插入另一个。当我发出 ajax 请求时，服务器以 500 内部服务器错误响应我。查询是正确的，我不明白为什么会发生这种情况。

下拉菜单的PHP：

<?PHP 
    $languageMatrix = array();
    $currentLanguage = "";
    function show_languages_list(){
    global $wpdb;
    $table_name = "wp_languages_price";
    $prepared_query = $wpdb->prepare("SELECT * FROM ".$table_name."");
    $results = $wpdb->get_results($prepared_query );
    echo '<label for="'.'source'.'">Select source language:</label><select name="'.'source'.'" id="'.'source'.'" onchange="showTargetLanguages(this.value)">';
    echo '<option value="" disabled selected>Select language</option>';
    $sourceLanguages = array();
    foreach($results as $languageCouple){
        //echo '<option>'.$languageCouple->languages_1.' - '.$languageCouple->languages_2.'</option>';
        $languageRow = array($languageCouple->languages_1,$languageCouple->languages_2,$languageCouple->price);
        array_push($languageMatrix,$languageRow);
        //Create an array of unique languages
        if(!in_array($languageCouple->languages_1,$sourceLanguages)){
            array_push($sourceLanguages,$languageCouple->languages_1);
            echo '<option value="'.$languageCouple->languages_1.'">'.$languageCouple->languages_1.'</option>';
        }
        


    }
    echo '</select>';
    echo '<label for="'.'target'.'">Select target language:</label><select name="'.'target'.'" id="'.'target'.'">';
    echo '<option value="" disabled selected>Select language</option>';
    echo '</select>';


}
show_languages_list();?>

Ajax 调用：

function showTargetLanguages(sourceLanguage){
            if (sourceLanguage == "") {
                document.getElementById("txtHint").innerHTML = "";
            return;
            } else {
                var xmlhttp = new XMLHttpRequest();
                xmlhttp.onreadystatechange = function() {
                    if (this.readyState == 4 && this.status == 200) {
                    document.getElementById("txtHint").innerHTML = this.responseText;
                    }
                };
                //Target get_stylesheet_directory_uri()."/gettarget.PHP"
            xmlhttp.open("GET",'/wp-content/themes/hello-theme-child-master/gettarget.PHP?q='+sourceLanguage,true);            
            xmlhttp.send();
        } 
}

Ajax GET 请求的 PHP：

<?PHP

    $q = ($_GET['q']);
    function get_target_languages(){
        global $wpdb;
        $table_name = "wp_languages_price";
        $prepared_query = $wpdb->prepare("SELECT * FROM ".$table_name." WHERE language_2'=".$q."'");
        $results = $wpdb->get_results($prepared_query );
    }
    get_target_languages();
?>

我做错了吗？非常感谢您抽出宝贵时间！