PHP/mySQL newb question

I am trying to update 20 records in a mySql table. I want to use a for loop and update the 20 records by a 'key'.

This code works. It updates *one record (I copied the PHP 'UPDATE' sytax from GoDaddy's 'Starfield' interface):

mysql_connect("**.*.***.***",$username,$password) or die(mysql_error());
mysql_select_db("*******") or die(mysql_error());
$sql = 'UPDATE `*******`.`hot_topics` SET `phrase` = \'test45\' WHERE `hot_topics`.`key` = 2 LIMIT 1;'; 

Code (markup):

However, when I assign a value from a symbol ($i) to the variable 'key', it stops working. This is confusing me because:
1) The key field is an int in the mySQL data base.
2) I checked with an is_int function, and $i is in-fact an int.
3) And, it works with the above code.

This does not work (The only difference is changing the `key` = 1 ---> `key` = $i):

mysql_connect("**.*.***.***",$username,$password) or die(mysql_error());
mysql_select_db("*******") or die(mysql_error());
$i = 2;
$sql = 'UPDATE `*******`.`hot_topics` SET `phrase` = \'test45\' WHERE `hot_topics`.`key` = $i LIMIT 1;'; //changed 2 to $i

Code (markup):

Thanks.

 

Try this:

$sql = "UPDATE `*******`.`hot_topics` SET `phrase` = 'test45' WHERE `hot_topics`.`key` = '" . $i . "' LIMIT 1;";

PHP:

 

It's because php only converts variables in strings when they're in double quotes. Use this

$i = 2;
$sql = "UPDATE `*******`.`hot_topics` SET `phrase` = 'test45' WHERE `hot_topics`.`key` = $i LIMIT 1";

PHP:

 

Thanks! Both of your solutions worked.

 

you can do this by adding the new column i.e auto increment column in the data base. This will help in selecting all the row value range for which you for loop will be work. and your job will be easy.