如果PHP，PDO插入和更新stetement(PDO insert and update stetement with if PHP)

 我的疑问是： 
 
   $select_userid_query = execute_pdo_query("SELECT user_id FROM users WHERE username='" . $_COOKIE['username'] . "'");

   if ($select_userid_query == 0){

    execute_pdo_query("INSERT INTO user_status
    (user_id,last_activity_time) VALUES
    ((SELECT user_id FROM users WHERE username='" . $_COOKIE['username'] . "'),NOW())"
     , array($user_id, $last_activity_time));

   }
    else{
        execute_pdo_query("UPDATE user_status SET user_id = (SELECT user_id FROM users WHERE username='" . $_COOKIE['username'] . "'),last_activity_time= NOW()", array($user_id, $last_activity_time));
        }
 
 我想验证数据库中是否有记录，如果没有插入，如果只是用新的NOW()更新时间NOW() 
 
 任何想法我的语法错误？ 

my queries are :
 
   $select_userid_query = execute_pdo_query("SELECT user_id FROM users WHERE username='" . $_COOKIE['username'] . "'");

   if ($select_userid_query == 0){

    execute_pdo_query("INSERT INTO user_status
    (user_id,last_activity_time) VALUES
    ((SELECT user_id FROM users WHERE username='" . $_COOKIE['username'] . "'),NOW())"
     , array($user_id, $last_activity_time));

   }
    else{
        execute_pdo_query("UPDATE user_status SET user_id = (SELECT user_id FROM users WHERE username='" . $_COOKIE['username'] . "'),last_activity_time= NOW()", array($user_id, $last_activity_time));
        }
 
i want to verify if there is a record in the database and if not insert and if there's just update the time of that with the new NOW()
 
any ideas where's my error in the syntax?

原文：