my $sth = $dbh->prepare('
   SELECT *
     FROM post_translations
     JOIN posts
       ON post_translations.post_translation_id = posts.post_translation_id
     JOIN languages
       ON post_translations.lang_id = languages.lang_id
    WHERE posts.post_id = ?
      AND languages.lang_name = ?
');

$sth->execute($post_id, $language_name);

##</code><code>##

CREATE TABLE `languages` (
    `lang_id` TINYINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
    `lang_name` VARCHAR(60) NOT NULL
);

CREATE TABLE `post_translations` (
    `post_translation_id` INT(11) UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
    `post_translation_cat` INT(11) UNSIGNED NOT NULL,
    `post_translation_date` DATETIME NOT NULL,
    `post_translation_title` VARCHAR(255) NOT NULL,
    `post_translation_body` TEXT NOT NULL,
    `post_translation_lang` TINYINT UNSIGNED NOT NULL
);

CREATE TABLE `posts` (
    `post_id`, INT(11) UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
);

CREATE TABLE `post_to_translation` (
    `post_id`, INT(11) UNSIGNED NOT NULL,
    `post_translation_id` INT(11) UNSIGNED NOT NULL,
);

##</code><code>##

CREATE TABLE `languages` (
    `lang_id` TINYINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
    `lang_name` VARCHAR(60) NOT NULL
);

CREATE TABLE `post_translations` (
    `post_id`, INT(11) UNSIGNED NOT NULL,
    `post_translation_id` INT(11) UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
    `post_translation_cat` INT(11) UNSIGNED NOT NULL,
    `post_translation_date` DATETIME NOT NULL,
    `post_translation_title` VARCHAR(255) NOT NULL,
    `post_translation_body` TEXT NOT NULL,
    `post_translation_lang` TINYINT UNSIGNED NOT NULL
);

CREATE TABLE `posts` (
    `post_id`, INT(11) UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
);