existsArticle :: FromURL -> MySQL (Maybe Int64)
existsArticle fromURL prefix conn = onlyToMaybe . listToMaybe <$> query conn sql (Only fromURLHash)
  where fromURLHash = hex $ hash (pack fromURL)
        sql = fromString $ concat ["SELECT `id` FROM `", prefix, "_articles` WHERE `from_url_hash` = ?"]
existsArticle :: FromURL -> MySQL (Maybe Int64)
existsArticle fromURL prefix conn = onlyToMaybe . listToMaybe <$> query conn sql (Only fromURLHash)
  where fromURLHash = hex $ hash (pack fromURL)
        sql = fromString $ concat ["SELECT `id` FROM `", prefix, "_articles` WHERE `from_url_hash` = ?"]
existsArticle fromURL prefix conn = onlyToMaybe . listToMaybe <$> query conn sql (Only fromURLHash)
  where fromURLHash = hex $ hash (pack fromURL)
        sql = fromString $ concat ["SELECT `id` FROM `", prefix, "_articles` WHERE `from_url_hash` = ?"]