用查询替换变量

Question

I am pretty new to using mysql and variables in php.

I have this code

mysql_query("INSERT INTO `forum_threads` (`name`, `byid`, `cid`,
`content`, `time`, `lastreplied_time`, `lastreplier_id`) VALUES
('{$title}', '{$uid}', '{$cid}', '{$content}', '" . time() . "', '" .
time() . "', '{$uid}');") or die(mysql_error());

In my php file, I want byid to be the value of id in my table forum_users. So can I replace {$uid} with something that will get the value from forum_users. Because I don't think {$uid} is working correct.

I found this code

/* Non-existant forum account */ final public function
createForumAccount($uid) {
    $getHabboUser = mysql_query("SELECT * FROM
        `users` WHERE `id` = '{$uid}' LIMIT 1");

I assume that the function of that code is to get the {$uid} equal the id from the users table, I want to make the {$uid} to equal the id from the forum_users table.

Then I found this code:

final public function getUserData($uid, $var) {
    if($this->checkForAccount($uid) == true) {
        $check = mysql_query("SELECT `{$var}` FROM `forum_users` WHERE `uid` = '{$uid}' LIMIT 1") or die(mysql_error());
        return mysql_result($check, 0);
    }
}

That code wants the {$uid} to equal forum_users id. And that is exactly what I want, but it doesn't equal that, it equals the id from the users table instead, I assume it might collide with eachother or something.

How can I solve this? Can I replace {$uid} in my first code, so byid is selected instantly from forum_users? Can I make a new variable that equals forum_users.id?

Answer 1

First of all this sql query makes no sense. However I am also not sure your question either. If your wanting to change byid to id in your table then you must alter the table. But here is a cleaner version of your sql query. try:

mysql_query("INSERT INTO forum_threads SET name=\"".$title."\",byid=\"".$uid."\",cid=\"".$cid."\",content=\"".$content."\",time=\"".time()."\",lastreplied_time=\"".time()."\",lastreplier_id=\"".$uid."\" WHERE id=\"".$uid."\" LIMIT 1") or die("Error: ".mysql_error());
//You Change ID to byid

to change byid to ID

mysql_query("ALTER TABLE `forum_threads` CHANGE `byid` `id` int NOT NULL")or die("Error: ".mysql_error());
// this will change the column byid to id 

Just Remember Mysql_connect() and mysql API are old and not used after php 7 so start to learn mysqli api

http://php.net/manual/en/book.mysqli.php